FYI: As Assassin you can choose between tank and dps gear (duelist and force lord).

Since you downloaded and repaired the whole thing 3? times, I suggest a total reinstall. With a clean install should be able to avoid patching and repairing. Also, did you disable bit raider?

I checked now most companions on all my chars: only Khem Val behaves that way. Everyone else has same health as dps and heal. Tank stance has slightly more health and less power. Please fix!

Had to transfer back my old main that parked on a low pop server to get all datacrons recognized. On a side note: got all datacrons on 2 servers now.

I am 60 and have level 16 influence with Khem Val. In Tank Mode he has 68k health 2k bonus damage (force), as DPS he has 59k health and 2k bonus damage (force) but in healing stance he has 20k health and only 1.2k bonus damage (force). Other companions do not have a difference in health or bonus damage in between DPS and Healing stance. That must be a bug!

Take the legacy achievements (and not the codex entries since they are character specific) as base and auto unlock all datacrons if you have the datacron master achievement.

AT-AT Walker mount for up to 10 passengers! Tbh: Just a simple Landspeeder https://en.wikipedia.org/wiki/Landspeeder

It will be fixed by removing the chair from vendor on next reset, so don't wait too long. Whats is "literally a level 5"??? Yeah you do. Nice story bro. And: There is no need to be scared and unreasonable right now. You can buy the 50 chairs without any risk (and you need to buy them now b/c they will be removed soon™).