Intro
Noorudin and his team (Maulvi Abdul Kareem and Mufti Sadiq) believed that Esa (as) had a biological father before they had ever met Mirza Ghulam Ahmad, they took this new belief from Sir Syed, who wrote it in 1880.  They all worked together in Jammu, with Noorudin being the boss.  Mirza Ghulam Ahmad seems to have sent his manuscripts to Jammu to be edited in 1890.  This book was most likely written entirely by this team of writers.

Nonetheless, Noorudin and his team held the belief that Esa (as) had biological father until 1904, wherein it is reported by Noorudin himself that he was forced to change his position on the order of MGA.  However, later on, the Lahori-Ahmadis seem to have reverted to this position, i.e. that Esa (as) had a biological father.  The Qadiani branch went on to call the miraculous birth of Esa (as) as less then a miracle and some sort of rationally explained phenomenon.  

In the reference that I will post, it is evident that Noorudin was the writer of Izala Auham, since it is written as follows:

“It is no wonder that God AlMighty might have given Jesus some technical knowhow so that by pressing a trigger or by somehow blowing on it, the clay toy took flight like a bird, or if it didn’t fly it might have walked. Because the Messiah, son of Mary had also been working as a carpenter with his father, Joseph, for twenty two years, and it is obvious that carpentry is a skill in which the faculty for inventing different sorts of machines and instruments is sharpened.” (Izala-e-Auham, Roohani Khazain vol 3 p.254 )

Conclusions
MGA and his team of writers always believed that Esa (As) had a biological father, til at least 1904, then, they seem to have switched directions and began explaining the “immaculate conception” as a natural phenomenon.

Some new references to consider and examine

“On a perusal of the Holy Qur`ān, this is what emerges as the truth, namely, that Jesus was fatherless; and this is a matter on which no question can come to lie. Where Allāh calls this birth as resembling the birth of Adam, it is an indication that in this birth there is an element of an extraordinary process of nature, to which a reference had to be made, for an explanation, by likening it to the example of Adam.” (Badr , May 16, 1907, page 3)

“Our faith and belief is this that Jesus was born of no father, and Allāh has the power to do all things. The rationalists, called Naturies among us, who try to establish that he was born of a human father they are making a serious blunder.The Lord God of such people is a dead Lord God. The prayers and supplications of such people are not granted who assume that Allāh cannot cause a child to be born independently of the agency of a human male in the role of a father. We consider a man who holds this view to have fallen out of the pale of Islam.” ( Al-Hakam, June 24, 1901)