Thats a step in the right direction.
Mollies grow pretty quick IME and so if you plan on putting your 2 remaining ones in the bigger tank when you can get it, make sure not to wait too long.
IMO, panda cories aren't a good idea for a 10g tank though some people disagree. What you heard of dwarf cories? They only reach and inch and do very well in 10g tanks.
There are some other really cool options for a 10g tank, but you will need to be a bit careful because of the angel. Some of these fish can be pretty small and even a small angel could eat them. However, if you want to get totally different stock, I suggest you look into chili rasboras, ember tetras, jellybean tetras, clown killifish, Norman's lampeye killifish, and celestial pearl danios.
If you would rather stick with what you have, you could get another platy or 2 or couple guppies for your tank once the other fish in a bigger tank.
Also, if your ammonia is high, you need to do more frequent or larger water changes. Since you said the ammonia is high, it wouldn't be good to add more fish right now.