the next time that there is a Terminator movie, I want the android to spend the entire movie sitting on its arse reading the newspaper and, while waiting for someone else to do something, to wonder if the computer that designed it really loved it after all.

I LOLed.

Given that Albus was a redhead and that both Albus and Aberforth have blue eyes

Both of which traits are recessive (I think?), so maybe it's possible, but--

Either that or wizards don't have to obey Mendelian genetics, and that notion just makes my head hurt.

--I'm guessing they don't. The passing down of magic doesn't make any sense at all.