A lot of people are complaining about vacuum and loot radar not being active while incapacitated.
Pablo was asked "What happens with the vacuum when they're incapacitated?"
He responds "uh, while they're incapacitated I'm not sure so I imagine it disables cos be disable a few other things but I'd have to verify".
Its clearly not set in stone right now, we only have a preview of PART 1 of the changes. Part 2 will focus on "abilities" so I assume they will make companions' unique mods/abilities more useful across the board which may end up being more important than if you have vacuum or not. Also, bear in mind panzer pets will also lose vacuum if their larva form dies so this is still putting every companion close to panzers. Sentinels will have a faster revive time than panzers if equipped with primed regen (giving sentinels 25s revive time), assuming medi pet kit does not affect panzer devolution since it might not be considered "incapacitated". They also will have 6s invulnerability after reviving. This means if you just want a pet for being alive as much as possible (which I assume won't be the case if the part 2 buffs a lot of abilities/precepts), djinn is the best closely followed by every other sentinel.
I would be interesting if primed regen and medi pet kit were able to be put on every companion (as well as other exclusive mods like link health armor shields) because then every companion could have access to a tiny 10 second revive time. I doubt they would do it, but it would be cool to have imo.