If you think that your tank can handle more fish then i'm sure they will be fine as long as you quartine them well and get them used to the water as pandas are said to be rather delicate, but i suppose you know all this already.
My experience with pandas haven't been too great. I got two one day and put them in a quarantine tank, after a couple of days i found one of them had got stuck behind the sponge filter sum how and died
. The other died soon after after moving him to the community tank.
Don't let me put you off these fish as that was only one time and i haven't seen them again in the shops.
Most of the cory species get along well together but they may stay a bit seperate from each other occasionally if the colouration is quite different.
Any how, if you do get them i wish you good look.
Ben