No, there is no way to resurrect normal NPCs, which is what companions become when they are dismissed from the party. I reported this for D:OS, but that is the intended behaviour. In the EE, quest items directly in a companion or henchman's inventory will be removed then they leave the party, at least.
I reported an issue where companions that leave with a DOT effect can die in the Hall of Heroes. Admittedly this is a pretty rare occurrence, so was give a low priority, but depending on how this may be addressed, it could also help with companions in the homestead while it is under attack.
Ah, I had hoped they would rethink that mechanic. It seems silly to cut out full parts of the story and have companions die because they just stand in one spot in the hall. Oh well, I've not played in a very long time so I'll just go back to a save before they died. The idea of doing that before when all that progress was still fresh in my mind was daunting to say the least. Now it's no biggie.
This game makes me so happy. Maybe it's because I'm not a super good gamer but I would like a little more hand-holding in terms of quests and such, maybe markers on the map? I know a lot of people don't want that though...maybe a toggle? I've just gotten so confused that I am doing side quests completely out of order! Oops. Maybe I should go finish up all my side quests and start again with a guide or something.
"You either die the hero or live to see yourself brought back in the sequel as an angsty magical terrorist." -Serious brownie points if you get the character to whom I am referring.-