46 gal and 2 to be rescued stunned fish?

So anyways the situation is as follows. My mother is an idiot and in her infinite stupidity she ended up with 2 blood parrots and a Chinese algae eater in a 10 gal tank. Tried to convince her to either return the fish and get something suitable for the tank or get a bigger tank, of course she as always knew better (yes shes the kind of a person that makes you want slam their heads against something hard for hours). Finally I just gave up, the fish have been there for a year and one of the blood parrots passed away. The CAE is around 4 inches long and the BP is also around 4 inches long, I plan on moving them to the bigger tank. The CAE never turned vicious (chances are he/she got beaten into submission by the surviving parrot). I plan on relocating the CAE if it starts being nasty (either give it to a petstore, put an ad somewhere)

Now my questions:

How big will these fish get once put in the bigger tank (I know they are stunned by now and their life spans have been shortened)?

Is it possible to add any other fish to the tank (if so what kinds)?