I'm not sure about "trope AUs", but I can certainly take realism off the table....

How about an unexpectedly broad-minded Straike re his less-than-manly stepson? (I know it's been done; but it was only done adequately.) Bonus points if it has something to do with a straight Straike's school experiences with a certain Mumps Jepson. And/or how Mumps got his name.

(Okay, theoretically this could be realism, I suppose.)