All valid points! As Aureolin mentioned, not having elbow pipes was a deliberate decision, because it would just complicate the code more than was necessary, which would make the game more bug prone. They definitely would've been useful, and I feel the game is worse off for not including them, but time constraints being what they are, this was the choice we (mostly I) made :)
I didn't even think of tooltips for buildings, I guess I was just so used to what they were I didn't think this could be a problem, but that's also valid.
Some sort of warning would've been nice, and I vaguely recall talking about it at some point, but I think we both just forgot all about it while tackling other issues :D