AS concluded in article , I too feel that Guru Nanak was not Muslim .
Abu Abeeda seems to have done extensive research and labour .
i wanna summerize article here as its too long
The Shahaadatayn (or the duel declaration of faith) is:
Laa ilaaha ill Allaah - There is none worthy of worship in truth except Allaah.
Muhammad ar-Rasool Allaah - There is none worthy of being followed in truth except the Prophet and Messenger Muhammad (upon whom be peace and blessings of Allaah).
instead of Shahaada , Guru Nanak told Babur
Guru Nanak is reported to have said to Babur:
There are millions of Muhammads, but only one God. The unseen is True and without anxiety.
Many Muhammads stand in His court.
So numberless, they cannot be reckoned.
Prophets have been sent and come into the world.
Whenever He pleaseth, He hath them arrested, and brought before Him.
The slave Nanak hath ascertained,
That God alone is pure and all else is impure
above is totally un islamic , and Kuffar as per Islam
Guru Nanak at Mecca
instead of praying towards, circumambulation around or kissing the Black Stone (hajr al-aswad) of the Ka'bah.
Guru Nanak answered
"Turn my feet in whichever direction God's House is not.
as mentioned above, constitutes Shirk billah (associating partners with Allaah).
Guru Nanak at Baghdad
Nanak also rejected the theological acceptance of the seven samawaat (heavens/ skies) - information that is an integral part to having correct belief in what Allaah has informed Muslims of vis-a-vis the unseen world (al-ghayb):
Guru Nanak says
There are nether worlds beneath nether worlds, and hundreds of thousands of heavenly worlds above.
If you try to write an account of this, you will surely finish yourself before you finish writing it.
Baba Farid and Kabir was also disbeliever
as
He is a disbeliever because he denied that He is up above (fi as-sama). Whoever denies that He is in Heaven has committed blasphemy."
Baba Farid say Creator in Creation
Fareed, the Creator is in the Creation, and the Creation abides in God.
Whom can we call bad? There is none without Him. ||75||Guru Granth sahib
Regards