Question

How do I indicate an alternative father and line, without removing the existing but uncertain father/line?

Answer 1

Since you can only connect one father, (1) connect the most likely father and mark him uncertain, (2) in the bio, discuss the two theories of parentage, the evidence for both, and why you think one is more likely than the other, and (3) in that bio discussion, link to the profile of the non-connected father.

Answer 2

I tend to add all of that type of info in the Biography.

Answer 3

I usually add a section for Reseach Notes, and put the details there and include links to "alternate" parents with explanation as to why this might be so etc.

Answer 4

Just to add to the other answers, it's good to know that a 'Research Notes' section is a level 2 section.  See here for more details: https://www.wikitree.com/wiki/Help:Biographies .

Answer 5

Thanks all for the very helpful responses.  I'll write up the alternative line in the notes, although I believe it is the more likely line, to avoid undoing all the work others did to create the further tree under the existing father.