Those names make no sense as injuries. I would name them like so:

Jinxed- Impaired Vision (encounters often refer to luck as awareness. also items like Warning Mirror, Lantern and skills like Listen, Spot Hidden, etc.)
Tainted- This is a bit more difficult, but maybe something like Face Burns (it's hard to convince people when your face is deformed)

They're really not. I would have assigned those to the Madness deck (though "Cowardice" or something probably would have been better than "Tainted"). Amnesia might have worked well as an injury.

There's Memory Loss as an inury...

Also, being a coward is not a mental problem. In fact, running away in face of the horrors in arkham is quite normal. The investigators that stick around are the abnormal ones.

Then it would be a different form of Paranoia. A general phobia or a haunting memory then? I can easily see a penalized Will being the result of a madness... but what to name it is a different story. It looked like FFG aimed to just fit all the stat penalties into the Injury deck.

you mean post-traumatic disorder? that could work, I guess. for a madness that is

I like Weak Heart: Horror damage is deducted from both Sanity and Stamina. (It's not a real injury of course. It's my own creation.) I suppose a nerfed version would be: any time you take Horror damage, deduct 1 from Stamina.

I dunno, Jinxed and Tainted might not make sense as literal injuries as such, but if you understand "injury" as referring more generally to the long term consequences of getting beaten up by a cosmic abomination, then it's reasonable enough that this would include things like bleeding soul ichor and having an improbably bad day.