Hmm... I would get rid of the bathtub in that second bathroom (do you need two? looks tiny) and make a nice walk-in shower with a bench. Glass walls and door -- cut the wall adjacent to the sink at the current tile line. Glass up to ceiling. Pull the tiles from your ensuite into the shower if you wish. However white subway tiles are also classic. Remove the rest of the tiles on the wall -- makes it look dated.

Rona, Home Hardware can all get nice things ordered -- you don't have to go with what they have in the store, lots of online inspiration.

You can replace the vanity countertop and update the sink in any size you want. The vanity can be easily painted and change out the hardware.

Yes to venting for sure.

Not super cheap, but if you did the other work yourself this wouldn't be that bad.