Lore wise:
I've heard that the resulting child from a 'Woman' with an Incubus would
be a witch but what would happen if it was a guy and vice-versa?

Did a bit of looking around and I honestly couldn't find an answer to this
besides than the reason lore goes for the opposite sex in the first place,
so they could produce their kids, The kids can be witches and warlocks and
so on and so on, Keeping that part as a footnote so that the resulting
baby could really be the star of the story.
Like Blue Exorcist ╹‿╹)

Now REALLY curious, I'd thought I'd pass the question along, seeing if
there is a common outcome with this sorta thing happening. Would that
person become possessed, Become a demi-fiend or would be no more
special than meeting someone on tinder or Grindr?