I don't know if this is known by all yet or not but I just found this out.

I tried going to Dead Money with Boone and Rex and lost both of their perks. Then I tried going with Cass and Rex and I lost Rex's perks, but I still had Cass's perks. So to do it all you need is Cass and Rex as companions and enter the bunker they will both get stuck behind and Rex will go away and it says he returned to wherever he goes back (to Freeside if I recall correctly) and you lose his perks but Cass gets stuck in the bunker and she still registers as a companion and you still have her perks. Which is really good for the alcohol becasue there is so much alcohol to drink at the Sierra Madre and you don't have to worry about addiction or negative effects which makes it a lot easier especially when you need easy strength boosts.

-Like I said I'm not sure how many know this yet so I figured I would put it out there in-case anyone needs the alcohol perk there. Also, I only experimented with Rex and Cass together so I dunno if it would work if she was alone or with EDD.

I hadn't heard of this but good to know.

I have not heard of this yet, but sounds cool will sure be helpful as there is plenty of booze to drink at the sierra madre.

I have not heard of this before but just tried it out, very useful.

I'm using a mod that allows having ALL the companions (yeah, I know, its a bunch) and on starting Dead Money only Boone and Rex leave. It seems that I have all the other perks given by the remaining companions.