Hey Eli -- welcome to Pond Boss.
Yes, those are largemouth bass. They are eating something because they look pretty healthy.
My guess is that the pond also has bluegill in it. Get some worms, and moderately small hooks, about a #4 (not 4/0) bait hook. Some small bobbers would be good too. Spend an hour or two going around the pond edge fishing with the worms.
Let us know what other kinds of fish you get, and their approximate sizes. Photos like you posted above would be perfect.
It is getting a little late in the year and the fish are probably starting to get sluggish because the water temps have dropped quite a bit lately.
Before stocking more fish, you need to get an idea of what is in there. With the size of the bass in your top photos, small stockers wouldn't even provide a decent snack for them. This fish would eat the new small fish pretty quickly.
Ken
