3 guppies, some cories, and some ghost shrimp would be good.
cories like to be kept in groups of 6 or more, so i think maybe some dwarf cories might be the best but i have no experience with cories so could someone say if cories like to be in groups of three? i think three or four is the most that would fit nicely into a ten gallon, but 6 might do fine.
for the air pump, i think it will be fine without it, but its hard to be sure. a biowheel filter runs the water through a lot of air so it should be ok.
EDIT: the guy above me wrote while i was writing so i didnt see his post. but i would disagree and say that an air pump is not necessary. he seems to think that cories do fine in groups of 3, which is likely, but i think only two is not enough.