I have only just skimmed through the last couple of pages of the thread, so I apologise if this post is not relevant or doesn't answer a question, but it did seem to me as though this information may be useful here.
Muslims believe that the shahadah is without value unless it is earnest.
The Qur'an and the ahadeeth are the ultimate sources for knowledge in Islam. We find contained in them the reality of the conditions necessary for the "shahadah." Islamic scholars have therefore developed, based on the data of the Quran and ahadeeth, essential criteria for an expression of the shahadah to be earnest. These criteria are generally divided into seven or eight or nine individual criteria; the varying numbers and orderings are not due to disagreements about what the criteria actually are, but rather different ways of dividing them. The conditions are headed in black. I have adapted this from various sources to try to make it as easy to read and understand as I could.
In the first part of the shahadah, the first pillar is the pillar of negation (there is no God), whilst the second is the pillar of affirmation (except Allah). What is meant by negation is to negate divinity and worship for anything except Allah, the Most High. What is meant by affirmation is to affirm divinity and worship only for Allah the Most Perfect; for it is He alone that is the true Deity. So whatever else is taken by the unbelievers as deities to be worshipped are in fact all false and futile: "That is because Allah is the Truth, and that which they call upon other than Him is falsehood.." [Surah al-Hajj 22:62]
Nobody is associated in Allah's exclusive Divinity. Whether it is assuming that Jesus is also divine, or that there are many gods, or that God has a son, or that God is composed of a trinity in which there are other godheads or persons, none of that Islamically constitutes worshipping Allah alone and having Him as sole Deity.
Imam Ibn al-Qayyim said: The significance of ash'hadu an laa ilaaha illallaah (I bear witness that there is no God but Allah) in affirming divinity and worship for only Allah is far greater than just saying that Allah is an ilaah (God). This is because the saying that Allah is an ilaah does not negate divinity and worship to other than Allah. This is different to the saying: laa ilaaha illallaah (there is no God but Allah); which obligates restricting divinity and worship to only Allah.
All the messengers of Allah told their people none has the right to be worshipped except Allah:
Allah said: "We did not send any Messenger before you, except that We revealed to him that none has the right to be worshipped except Me; so worship Me." [Surah al-Anbiyaa 21:25]
The second part of the "Shahadah" i.e. "Wa ash'hadu anna Muhammadan abduhu wa rasuluh" means that the Prophet Muhammad (peace be upon him) is the servant and messenger of Allah. No one should be in any doubt about this matter. In fact, the Muslim has to obey the commands of the Prophet (peace be upon him), to believe in what he has said, to follow his teachings, to avoid what he has forbidden, and to worship Allah alone according to the message revealed to him.
The conditions can be described briefly as follows:
1 Knowledge
That is, one must have the basic and general knowledge of what is meant by the shahadah. One must understand what the shahadah is affirming and what the shahadah is negating.
Allah says in the Qur'an;
"So know that there is no God save Allah....." (Surah Muhammad 47: 19).
When one testifies to something, one must know what it is that he is testifying concerns. Obviously, a testimony about something that one does not have any knowledge about is absolutely unacceptable.
2 Certainty
The heart must be firmly certain of the meaning of Shahadah without a blemish of doubt. This is the opposite of doubt and uncertainty. We must, in our hearts, be absolutely certain of the truth of the shahadah.
3 Sincerity
That is, when we make the shahadah, we must do so solely for the sake of Allah. We must not do it for any other reason. And we must not do it for anyone else's sake. In this manner, the meaning of sincerity is opposite of Shirk or ascribing partners with Allah. We became and remain Muslims solely for Allah's sake.
4 Truthfulness
This means that when we say the shahadah, we are saying it honestly. We actually mean it. We are not lying when it comes to our testimony of faith. It is truthfulness which prevents hypocrisy. Indeed, the hypocrites uttered it with their tongues, but did not inwardly believe in what it signified.
5 Love and affection
Love for this testimony and having love and pleasure for it. That is, the believer loves this shahadah, he loves the implications and requirements of the shahadah. This is a necessary condition of the shahadah. If a person makes the shahadah but does not love the shahadah and what it stands for, then, in fact, his faith is not complete. The true believer, the one meeting the conditions of the shahadah puts no one whatsoever as an equal to Allah in his love.
Allah says in the Qur'an:
"Yet of mankind are some who take unto themselves (objects of worship which they set as) rivals to Allah, loving them with a love like (that which is due to) Allah only. However, those who believe are stauncher in their love of Allah" (al-Baqarah: 165).
The Messenger of Allah, peace be upon him, said: "There are three (qualities), whoever possesses them, will taste the sweetness of Iman (belief): to love Allah and His Messenger more than anyone else, to love the Muslim only for the sake of Allah, and to dread returning to kufr (apostasy) as he dreads being thrown in fire." ( Bukhari and Muslim.)
Allah says:
Say (O Muhammad SAW to mankind): "If you (really) love Allah then follow me , Allah will love you and forgive you of your sins. And Allah is Oft-Forgiving, Most Merciful." (3:31)
The Prophet, peace be upon him, also said: "None of you shall (really) believe until I become dearer to him than his own father, and son and all mankind." ( Bukhari and Muslim.)
6 Submission and compliance
This implies the actual physical enactment with our deeds of our shahadah. In fact, this is one of the main meanings of the word Islam itself, "the submission to the will and commands of Allah." This is what Allah commands in the Qur'an:
"Turn unto Him repentant, and surrender unto Him" (al-Zumar: 54).
Allah has praised those who submit to His command by their actions. Allah says:
"Who is better in religion than he who surrenders his purpose to Allah while doing good" (al-Nisa 4:125).
Actually, Allah has clearly made it a condition of faith that one submits to the command of Allah and His messenger.
Allah says: "But nay, by your Lord, they will not truly believe until they make you [the Messenger of Allah] judge of what is in dispute between them and find within themselves no dislike of which you decide, and submit with full submission" (al-Nisa 4:65)
Submissive compliance is also achieved by fulfilling the rights of the shahadah- which are the obligatory actions - with sincerity to Allah and seeking His good pleasure.
Allah, the Exalted, says: "And he who submits himself to Allah, and does good, he has surely grasped a strong handle." (Quran 31:22).
Allah also says:" And turn you to your Lord, and submit yourselves to Him." (Quran 39:54).
7 Acceptance and conformity
If a person has knowledge of and certainty in the shahadah, this must be followed by acceptance, with the tongue and heart, of whatever that shahadah implies. This is achieved by acting upon what Allah has commanded and abandoning whatever He has prohibited.
The believer accepts whatever the implications of the shahadah are. This also means that he believes in whatever is stated in the Qur'an or stated by the Prophet (peace be upon him), without any right to choose what he wants to believe and what he wants to reject.
Allah says in the Qur'an:
"Do you believe in part of the book and reject part of it? And what is the reward of those who do so, except humiliation in the life of this world, and on the Day of Resurrection they will be sent to the most dreadful doom." (al-Baqarah: 85).
Allah says "Indeed in the Messenger of Allah (Muhammad peace be upon him) you have a good example to follow for him who hopes in (the Meeting with) Allah and the Last Day and remembers Allah much."(33:21)
And Allah also says:
....And whatsoever the Messenger (Muhammad peace be upon him) gives you, take it, and whatsoever he forbids you, abstain (from it) , and fear Allah. Verily, Allah is Severe in punishment. (59:7)
O you who believe! Obey Allah and obey the Messenger (Muhammad peace be upon him), and those of you (Muslims) who are in authority. (And) if you differ in anything amongst yourselves, refer it to Allah and His Messenger ( peace be upon him), if you believe in Allah and in the Last Day. That is better and more suitable for final determination.(4:59)
But no, by your Lord, they can have no Faith, until they make you (O Muhammad ) judge in all disputes between them, and find in themselves no resistance against your decisions, and accept (them) with full submission. (4:65)
Say (O Muhammad peace be upon him): "Obey Allah and the Messenger (Muhammad peace be upon him)." But if they turn away, then Allah does not like the disbelievers (3:32).
Peace.