And yes, a little bit of oil vapor if you let it run for longer than ten second bursts, but no big deal at all.
If you like to see the readings from the gage on the bleeder, take it off of the bleeder, use little pieces of the clear hose and the three way hose connecter to put it in the line between the carboy and the pump.
Where does this oil vapor go? Oil vapor in a well ventilated room is fine, I guess. The risk of oil vapor in my carboy, not so much.
I like the idea of cannibalizing the brake bleeder to get you where you need to go (especially the gauge).
I may just go down this road myself.