Generally julies and calvus do well together in smaller tanks, that's why I suggested it. 29 gallons isn't a lot to work with, so you just have to be careful from the beginning with stocking, and everything will work out much better in the long run.
You could always do a species only tank with one of the smaller neolamps like the lelupi or brichardi. And I have heard of people keeping julies and lelupi in 29gallon tanks before with no other fish and things be OK, but leluip can be iffy and it depends on the personality of the fish. So what might work for you might end up a disaster for me. I've not tried that myself, so I can't speak much on it.
With the julies, you could get away with some of the more fiesty shell dwellers like some of the occies or even maybe some of the multies, but i wouldn't expect a large amount of fry to survive from either.