Yes, you can certainly have African Dwarf Frogs in a community tank.. you DO have to be careful about feeding them. I have ADF in 2 of my community tanks (see my signature

, and they are all fine.. rather fat, in fact.
But I feed the whole tank their food, so the lucky bettas, cories and danios all gof Frozen Bloodworms. I did make sure sometimes to get the food to drop right on top of the frogs, either by using my fingers or long tweezers, as they do not see very well so are not always as good at getting their fair share.
Only think I would worry about is how tall your 29 gallon is.. since they need to come up for air from time to time (like betta's) they need a tank that is shallow enough for this.. I would say no more than 15" high..
I have mine with corydoras, bettas, and danios, and they are all fine and peaceful.
P.S. IMHO, I don't think a 2.5 gallon is big enough for a Frog and a Betta ... personally, I would say that tank is not big enough for any fish, certainly not a fish and a frog.. it might do okay with a couple of ADF when they are still babies, but.. once they grow to adulthood, I would go with min, 5 gallon for that..
Good luck! I love my froggies!