In the 32.5 gal
you can even add small fish like those with schooling behavior.
Funny you say "they can't be separated"...lol
My blue ramn lost her pair and they really change behavior when their friends go away, and they have a nice character for aquariums cause look like they truly love each other..lol
You are good with the 20gal, because u can add up to 10 guppy for each 20g, however you have some more fish in there
Also you have different species, so they have different water parameters, try to equalize things as well, like blue rams enjoy warm water like 76-80, while cories tends to feel better in water with 67F-70F, not counting the ph