[Theja]

The marriage ceremony between Muhammad and Khadijah were presided by an Ebionite Priest (a cult that denies the divinity of Christ).

So long as this priest and Khadijah were alive, Muhammad had only one wife. From them he heard some Bible stories, often mixed with Jewish myths surrounding the Torah and Bible characters.

Muhammad also would travel to Syria for business and had plenty of opportunities to hear the stories of Jesus and Christians from the Syrians.

Muhammad may be illiterate, but he possessed native intelligence and a quick wit.

So yes, the many similarities comes from his hearing from people he came across. In which case, to determine the accuracy of certain facts, one must go to the primary source (Bible) and not depend on hearsay (secondary source, which Muhammad heard).