I'm assuming some easy plants may grow but you are very limited in options. Also it will be hard to maintain since there is not alot of water. I agree you should get a larger tank. In my opinion, tanks less then 5 gallons are useless, except maybe a small shrimp only stock.
Walmart has a nice 5 gallon kit and all you would need is a 1500k light, also at walmart for just a few bucks. This will give you enough room to aquascape nicely and allow you to grow more plants.
On the 10 gallon, betta's may or may not work with other fish. It depends on the betta, and amount of hiding spaces you can create with wood and plants. You will get success stories as well as horror stories combing bettas with other fish, its a chance you would have to take, some of us wouldn't even try.
In my opinion, if your set on a betta, go 5 gallon. You can have the pants you want and some inverts. Snails would work, shrimp might be dinner. If you just want a nice active fw tank and don't need a beta, a 10 would be perfect. I have ember tetra in mine and they are very active. You can also have some small corys.