In regards to the Meharban Janamsakhi, Meharban was the grandson of the 4th Guru.
Points to note are:
1) Meharban led the Minas Cult which corrupted Sikh teaching.
2) Guru Arjan condemned the Minas and basic historical contents of the Janamsakhi ...........Sikhs didn't touch it for centuries until Dr Kirpal Singh resureccted it.
3) Meharban introduces the theory that Guru Nanak was an Avtar of King Janak, father in-law of Rama and father of Sita.
4) The Minas wanted the Sikhs to have a Hindu Pantheon.
5) They changed Guru Nanak's place and date of birth
6) Along with the Hindali's they placed Kabir above Guru Nanak. (the Hindali's wrote the Bhai Bala Janamsakhi, another fictious work)
7) Bhai Gurdas condemns and criticises Meharban. Read // 36-1 to 36 - 11 where the Minas are condemned and described as "hypocritical" and "spiritless evil persons"
8) Meharban and Prithi Mal insulted the Guru's face to face.
9) Bhai Buddha and Bhai Gurdas ousted the Meharban and the Minas from Amritsar
10) Meharban started calling himself the seventh Guru.....while his son Harji the 8th.
11) Meharban tried to corrupt Mulmantaar
Many historians (Hazari Prased Trivedi, Charlotte Vaudenville), have established Bhagat Kabir Ji's life span from 1398-1448
Guru Nanak never met Bhagat Kabir, as Kabir Ji was dead by the time Guru Nanak was born. Guru Nanak never recorded this meeting with Kabir Ji in his hymns, (like he did for other events, for example Nanau Chand at Kurukshetra SGGS 1289-1290, etc, etc). Neither did Shaheedi Bhai Mani Singh, the scribe of the Guru Granth Sahib, mention this monumentous encounter in his works, Gyan Ratnawali, or list Kabir Ji as a friend or companion in Guru Nanaks life. Neither did Bhai Gurdas mention this so-called meeting. And neither do the Kabir-panthis, (the followers of Bhagat Kabir) believe in this story.
I sinerely believe this so-called story of Guru Nanak meeting Kabir Ji is just another fairytale.
Bhul Chuk Maaf,
WaheGuru Ji Ka Khalsa,
WaheGuru Ji Ke Fateh!