bettas need at least 2.5 gallons and ADF's need at least 2.5 gallons as well.. putting them in anything less than 5 gals would be overstocking. I have a betta and a mystery snail in a 3 gal and even that is overstocking.. but I do 2 weekly water changes and the tank is cycled so it works ok but I wouldn't recommend it.
Meh if I was gonna do frogs I'd put em in their own tank. Plus my sister already has 2 of em. But I'll probably get 1 or 2 shrimp, Im afraid of Athena eating them lol.