Are my injectors correctly seated ??
 

When pushed around my injectors wobble a bit on their manifold ports...
Is this ok, or are they supposed to be firmly seated ?

Could it be a source for air leaks ?

The injectors, the plastic sleeves that hold them, and the rubber "O" rings are a typical source of air leaks. The injectors are held in by fairly large "O" rings. If the "O" rings are not dried out and crusty, you can wiggle the injectors around a bit. They are also easy to pull out if the "O" rings are still fairly new. If you're worried about it, pull an injector out and take a look at what it's seated into. The rubber should be nice and soft, and the injectors easy to re-install just by pushing them in. The plastic sleeves under the injectors are also sealed with "O" rings, but are more difficult to get to.

Well they certainly wiggle a bit, that's what caught my attention.
But now I'll have a better look.

I replaced mine following my rebuild. When I pulled the injectors everything was pretty crusty - and the injectors had some wobble prior to being pulled.

Even after replacing the injectors, sleeves, sleeve o-rings and injector o-rings there is still wobble.

Basically what I am trying to say is the the wobble won't offer any insight as to the condition of your sleeves and rings. You need to pull them in order to make that determination.

Keep in mind that the injector sleeves are "staked" into the manifold. You can see three tabs that hold them in place. While I had my CIS off I ground off the "stakes". I don't see how this can be done with the CIS on the car ... at least not while the engine is in the car.

I didn't stake them again after replacing the sleeves. They stay in place just fine without staking them.