The internal buss structure should just work without having to touch it. The only thing you really should do is changing the master output to whatever output you have on your system.
I have not come across that the names on busses change. Should be the name from the original session.
I get a lot of Pro Tools session sent to me for mixing. In my case I always import everything to my mix template. Then it's fast and easy for me to find my way around the session. If you just going to make some minor adjustments it might be better to just go with their original session.
Everyone works differently so the hardest part is often to figure out how everything is wired internally. But when you get the master output right it's often pretty straight forward.
And yes, when you don't have the plugin used, just get them to bounce that track for you and make the one with the plugin inactive.