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.