The only tool I found which was actually reliable was fielding VD trained 55+ Psi Strength units (and even then you still have to worry if the Provost is very close), so basically original X-Com.
What about:
1. your own voodoo
2. psi lightning rod
3. or just simple camping, spotting, eliminating and hiding
4. using weapons that don't hurt you with good-enough armor
5. ... I'm sure people will add a few more
And yes, I have tried and used 2/ and 3/ and can confirm they work consistently.
I didn't try 1/ yet as I am not that far in the game.
I will try 4/ at the next opportunity.
Where's the RNG with the new invisibility (which the idea assumed)? It's basically like smoke LoS range reduction vs a single unit (just as it worked in Apocalypse), and apparently will be items that enable you to detect invisible units further out.
You haven't specified what kind of invisibility it is. "Chameleonic carapace that features active camouflage" doesn't exist in OpenXcom, so I have to assume it is the same kind of invisibility as e.g. Catgirls have.... which is RNG in all its beauty, unless you carry some sort of motion scanners on steroids on all soldiers.
EDIT: some other special abilities you describe also don't exist, e.g. zombie which doesn't spawn a unit... or regenerating a fatal wound