I read that it is better to get a male if you have a female but I probably would stick with another girl. I don't want to deal with marking and it seems like a lot of males do that (neutered or not). Having a dog in a belly band all the time (especially when visiting other homes) doesn't sound like fun.
And how do they use wee pads if they are at the lifting leg stage?
Am I overthinking the pee pee thing?

Probably.
Lucky you...a new baby to look forward to!