Had the same problem post Dead Money.. how this is missed I don't know? I would think the first thing they'd bug test is that you can get your companions back after the DLC -- considering they are forced away to start it..
To make things worse I picked up Rex to replace ED-E since I gave up on trying to get to him without him being hostile.. so I got Cass to replace Veronica just to start up a new team with Rex.. and Rex completely disappeared from the game when I sent him back to Lucky 38 for attacking someone for wearing a :swear: hat..
So I had to throw away 2-3 hours worth of wandering, to reload a save about 10 saves back prior to picking up the Cass line of quests, in order to get Rex back with Veronica.. but still doesn't feel right with having them two together..
After Xmas I might go back in and load a save prior to Dead Money.. and rather than tell ED-E and V to wait at Lucky 38.. try and send them back there through dialogue and see if it works, and they don't go back to Primm and the trading post.. I didn't realize the difference in having them wait at Lucky 38 vs using dialogue to part ways and send them there that way until after the DLC with Cass.. maybe he won't go back to Primm and be OK.. but that means replaying Dead Money which I didn't really enjoy..
..or.. just reload, screw going to Sierra Madre, never go to the bunker, and quest from 30-35 in the Wasteland and keep ED-E with me..