Relatedly, attaching furring strips/wooden framing to concrete block wall is now my nightmare.

I popped the relevant bit of paneling up without disassembling everyhing, and wodged sealant all over the leaky place, so we're letting it cure and we'll see if it lasts through tomorrow's storm. We probably actually need to dig up the outside of the foundation, but I don't want to, and that might actually make it worse anyway, because the outside of the foundation has a clay layer around it as sealant that I don't think we could put back. There is a reason I made all my design choices around the idea that there would be leaks.

Ugh, home ownership.