Say: "None in the heavens and the earth knows the Ghaib (Unseen) except Allâh"
And to Allâh belongs the Ghaib (Unseen) of the heavens and the earth, and to Him return all affairs (for decision). So worship Him (O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭ ﺳﻠﻢ) and put your trust in Him.
Regarding what you mentioned about the obliteration of the self, when humans claim to be united with the Essence of Allah, and what you quoted from Shaykh AlIslam Ibn Taymiyyah on this matter, condemning this condition, but without declaring it as blatant Kufr, I understood what you wrote. However, what the critics said about it, that it is blatant Kufr, is sound and valid, if the person in this state is of a sound mind and says similar words to those quoted from Abu Yazid AlBastamy, who said, "There is nothing in this Jubbah (a long garment) except Allah (meaning unity with Allah)," and those who say, "I am the Truth" or "Glorified be me". But if the person who said such words is ruled to have lost their mind, as was indicated by Abu Al'Abbas, who, as you reported, said that they would have a sound excuse, because the Pen is stopped from recording the deeds of those who have lost their minds.
The scholar Ibn AlQayyim (may Allah be merciful to him) mentioned this meaning in: "Madarij AlSalikin", vol. 1, pp. 155158. I ask Allah to grant us and you understanding of His Din (Religion) and deep insight into His Truth, and protect us and you from the misleading Fitnah and the incitements of Satan, as He is the best One asked for help.
In regard to what you wrote about celebrating Mawlids (the Prophet and pious people's birth days), there is no doubt that this is Bid'ah, if it is practiced as an act of 'Ibadah (worship). etc., and I say that it is certain that the people who celebrate Mawlids think that they are performing an act of 'Ibadah that will bring them nearer to Allah. So they are without doubt committing Bid'ah, because the Prophet (peace be upon him) never did such a thing, nor did he permit or endorse it.
His Sahabah (may Allah be pleased with them) did not do this either, and they were the best generation and the most perfect in love of all people to the Prophet (peace be upon him) and the most knowledgeable of the purified Shari'ah, neither did those after them from the righteous early generations of Islam. This is so if the celebrations are free of other acts of Munkar (that which is unacceptable or disapproved of by Islamic law and Muslims of sound intellect), which is not possible seeing the ignorance and exaggeration that overpower most of the souls. They often involve major Shirk and sins, which is not hidden from people like yourself.
"Anyone who imitates a people is one of them."
Conclusion: I read the chapter you mentioned in your paper and reflected upon it, and found it very useful and beneficial. May Allah multiply your reward and increase our knowledge and guidance. However, I have some remarks on it, in addition to the previous ones. They are as follows:
Muhammad (peace be upon him) is one of the best ways to polish the heart and one of the best ways to purify the soul...," but stating it to be the best I cannot see to be right. In my opinion the correct view is that the best way to polish the heart is Dhikr (Remembrance of Allah) and reciting the Glorious Book (the Qur'an), and if you add to this frequently sending peace and blessings on the Prophet (peace be upon him), this will be goodness upon goodness.
Those who believed (in the Oneness of Allâh Islâmic Monotheism), and whose hearts find rest in the remembrance of Allâh: verily, in the remembrance of Allâh do hearts find rest.
"Iman (Faith) has seventyodd branches, the best of which is saying: La ilaha illa Allah (there is no deity but Allah)."
"The best thing that I or the prophets before me said is: ' La ilaha illa Allah'."