Are you sure that isn't just the shipping size? I would be really surprised to see a variety that was so much smaller than average for parrots, which I would guess average size for is about 6" based on my own observations. I looked and couldn't find anything on size for this variety except shipping sizes between 1" and 2.5".
Regardless, I've had smaller 2"-3" female convict cichlids survive and thrive with larger CA cichlids. In general, the larger fish don't see them as a threat and ignore them as long as they can't fit in their mouths, and none of the fish you have on your list have especially large mouths. I won't keep parrots, but I know they can be fairly aggressive. So a lot of it is going to be based on tank size. In a 6' tank with plenty of shelter, a smaller parrot may be okay.
Like I said though, I really doubt that 2.5" is all the larger it will get. And if you don't have at least a 150 gallon tank, I suggest you rethink your stock completely.
WYite
