Twiss. . . CONGRATULATIONS on your new little Froggy!
ZooMed Frog and Tadpole bites are fine for the frog, as long as s/he willl eat them! Pre-soaking them is a great idea, and you can also supplement the pellets with brine and bloodworm. . . wet frozen, not freeze dried. They'll eat almost anything meaty. Feeding with tweezers (or by hand or with a turkey baster) is fine, too.
It's fine to keep him with a Betta, lots of people do. The main concern here, aside from aggression from the fish (which doesn't seem to be a problem for you!), is that the frog gets his fair share of food and the Betta doesn't get overfed. As long as you're feeding with tweezers, this shouldn't be an issue - just keep it in mind. If they aren't fed by hand, ADF are slow and messy eaters, the Betta (or any other fish) would easily eat everything before the frog has had a bite - again, not a problem if you're feeding by hand (or tweezers)
ADF ARE social, but they aren't like shoaling fish - they do perfectly fine on their own. You may see more activity from them when they're kept in groups, but an ADF alone will be perfectly happy and content. If you DO choose to get another ADF, you will have to move up to a bigger tank. You could keep 2 ADF in a 5g only, or 1 frog + 1 Betta - but anything over that will require a larger tank size.
To the best of my knowledge frogs don't hurt Betta fish, lol! I've read the occasional tale of one latching onto a Betta's tail thinking it was food, but they figure it out pretty quickly, and let go. Not sure where that idea came from - ADF are really sweet little creatures, and have no teeth, lol!
Hope this helps!
ETA: In case I read that wrong, ADFs do NOT 'attack' other ADF, either. . . females can get pushy at meal times, and when they feed, since they're so blind, they DO have a habit of accidentally nomming on the others flippers and noses, but again - no harm done, and a quick release when they figure out what happened. Silly frogs...