Salam hellokappa
4) Qur'an 4:15 "... confine to house for the woman until Death claims her or when Allah ordain for her in another way":
I don't understand why the (lewd) men can repent and be forgiven but the woman is given a harsh punishment (and cruel from the standpoint of psychology). From my understanding, God has ordained the women in the form of 100 lashes. The only excuse I can think of is that men has to go out to work... but it's still no excuse to give this unfair punishment. There's many passages in the Qur'an that says that both genders are equal in the eyes of God, but this feels contradictory. Could someone explain this verse to me more?
Brother islamiclife is right that these verses were just the preliminary commandments regarding adultery/fornication.
004.015 وَاللاتِي يَأْتِينَ الْفَاحِشَةَ مِنْ نِسَائِكُمْ فَاسْتَشْهِدُوا عَلَيْهِنَّ أَرْبَعَةً مِنْكُمْ فَإِنْ شَهِدُوا فَأَمْسِكُوهُنَّ فِي الْبُيُوتِ حَتَّى يَتَوَفَّاهُنَّ الْمَوْتُ أَوْ يَجْعَلَ اللَّهُ لَهُنَّ سَبِيلا
004.015 If any of your women are guilty of lewdness, Take the evidence of four (Reliable) witnesses from amongst you against them; and if they testify, confine them to houses until death do claim them,
or Allah ordain for them some (other) way.
Al-Qur'an, 004.015(An-Nisa [Women])
Text Copied from DivineIslam's Qur'an Viewer software v2.910
The end of the verse tells us that Allah will ordain for them a way other than confinement and He does so. Following is Modudi's explanation of the verse
These injunctions are necessarily of a preliminary nature since the people of Arabia were neither used to obeying the orders of any established government, the verdicts of any courts of law nor to following any legal code; it would therefore have been unwise to try to force acceptance of a penal code upon them so soon after the establishment of the Islamic state. In due course, the punishments for unlawful sexual intercourse, for slanderous accusations of unchastity against women, and for theft were laid down in their definitive form and served as the basis of that detailed penal code which was enforced by the Prophet (peace be on him) and the Rightly-Guided Caliphs.
http://www.islamicstudies.info/tafheem.php?sura=24
Ibn Kathir's explanation
`Some other way' mentioned here is the abrogation of this ruling that came later. Ibn `Abbas said, "The early ruling was confinement, until Allah sent down Surat An-Nur (chapter 24) which abrogated that ruling with the ruling of flogging (for fornication) or stoning to death (for adultery).'' Similar was reported from `Ikrimah, Sa`id bin Jubayr, Al-Hasan, `Ata' Al-Khurasani, Abu Salih, Qatadah, Zayd bin Aslam and Ad-Dahhak, and this is a matter that is agreed upon. Imam Ahmad recorded that `Ubadah bin As-Samit said, "When the revelation descended upon the Messenger of Allah , it would affect him and his face would show signs of strain. One day, Allah sent down a revelation to him, and when the Messenger was relieved of its strain, he said,
«خُذُوا عَنِّي، قَدْ جَعَلَ اللهُ لَهُنَّ سَبِيلًا، الثَّيِّبُ بِالثَّيِّبِ، وَالْبِكْرُ بِالْبِكْرِ، الثَّــيِّبُ جَلْدُ مِائَةٍ، وَرَجْمٌ بِالْحِجَارَةِ، وَالْبِكْرُ جَلْدُ مِائَةٍ ثُمَّ نَفْيُ سَنَة»
(Take from me: Allah has made some other way for them. The married with the married, the unmarried with the unmarried. The married gets a hundred lashes and stoning to death, while the unmarried gets a hundred lashes then banishment for a year.)''
The verse which was revealed later is
024.002 الزَّانِيَةُ وَالزَّانِي فَاجْلِدُوا كُلَّ وَاحِدٍ مِنْهُمَا مِائَةَ جَلْدَةٍ وَلا تَأْخُذْكُمْ بِهِمَا رَأْفَةٌ فِي دِينِ اللَّهِ إِنْ كُنْتُمْ تُؤْمِنُونَ بِاللَّهِ وَالْيَوْمِ الآخِرِ وَلْيَشْهَدْ عَذَابَهُمَا طَائِفَةٌ مِنَ الْمُؤْمِنِينَ
024.002 The woman and the man guilty of adultery or fornication,- flog each of them with a hundred stripes: Let not compassion move you in their case, in a matter prescribed by Allah, if ye believe in Allah and the Last Day: and let a party of the Believers witness their punishment.
Al-Qur'an, 024.002 (An-Noor [The Light])
Text Copied from DivineIslam's Qur'an Viewer software v2.910
The explanation of this verse is really long. I'll just give a link
http://www.islamicstudies.info/tafheem.php?sura=24
In short, if a married person commits adultery then whether man or woman, he/she should be killed and if an unmarried person commits fornication then whether man or woman, he/she should be flogged. Islam does discriminate regarding men and women when it comes to punishment but that goes in favour of women. Following are the excerpts of Modudi's explanation of the verse given in the link above
While flogging, a man should be made to stand and a woman to sit. In the time of Imam Abu Hanifah, Qazi Ibn Abi Laila of Kufah got a woman flogged while she was standing. The Imam took a strong objection to it and openly declared it to be a wrong thing.
At the time of flogging, the woman should be in her full dress: her clothes should rather be tied down on her so that no part of her body might be exposed; her thick clothes only will be taken off; but in regard to a man, there is some difference of opinion. According to some jurists, he will be allowed to remain in his pyjamas only, and according to some others, the shirt will not be taken off.
On a side note, the flogging is not carried out in a barbaric nature. Read point 23 of explanation in the link.
5) Women are allowed to divorce in Islam; however, is it harder for them to divorce their husband?
Women are free to choose their husband. After marriage, a Muslim woman can take divorce from their husband
Bukhari Volume 7, Book 63, Number 199:
Narrated Ibn 'Abbas:
The wife of Thabit bin Qais bin Shammas came to the Prophet and said, "O Allah's Apostle! I do not blame Thabit for any defects in his character or his religion, but I am afraid that I (being a Muslim) may become unthankful for Allah's Blessings." On that, Allah's Apostle said (to her), 'Will you return his garden to him?" She said, "Yes." So she returned his garden to him and the Prophet told him to divorce her.
So it is that easy for a woman to get a divorce under Islamic laws.
I'm living in a country with a lot of Muslims and I notice that it's easy for the men as they need to say "I divorce you" x3 (...which is supposed to be done on 3 different occasions, but there are bad Muslims who does it in one go, and it was accepted =___=

.
There is a difference of opinion whether 3 at the same time means 3 or 1. But saying "I divorce you" x 3 at the same time is a sin, there is no difference in opinion in that.
On the other hand, the women have to go to the court to appeal to divorce where the person in charge of the appeal can deny her that right. So many women who wants divorce, simply don't bother because it's a hassle or they don't have the time or means to do so. Sorry for the longish story; basically, I want to know whether it's harder for a woman to seek a divorce as opposed to a man.
Ideally in an Islamic state, the judicial proceedings should not take a lot of time and if a wife is mistreated then her right should be given to her by the judiciary without hurdles. But if an Islamic country does not follow Islamic rules, then it is no fault of Islam.
Peace