Shrimp would be a nice addition as well, RCS are some of my favs and are cheap as well.
In addition, the 1" / gallon rule was a good base line to follow for quite a while but people try to look at the bio load of fish as well. For example a pleco or gold fish is going to add way more to the bio load than most other similarly sized fish. I like to use
AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor as a base line to figure out stocking levels on my tanks.
For example, on a 10g tank 5 guppies and a shoal of 6 corys gives a 122% stocking level. It is a good base line comparison but only really a guideline. I took my stocking level up to 150% and had absolutely no issues at all. If you wanted to save on some stocking space you could go as low as 4 cory cats, although I would say that is the absolute minimum.