I wouldn't say there's too many restrictions when young cause there really not powerful enough to do much damage yet. They may chase though. Redhump geos should be ok cause those geos are pretty bold themselves. I had a gd group of altifrons with my dats and nothing really stops geos from constantly sifting the sand for food unless something demolishes them. Just when the dat gets big, the geos may have to be removed. Just keep an eye on things...I've always found that dats and cichlids aren't the best combo, but there's not much to worry about till the dats get big enough to hurt them
For now I would stick with what you have for stock since its only a 10gal, but large top dwellers and almost any medium to large bottom dweller should work in the long run. And remember dats can get up over 2feet in length if properly cared for, so a large tank will be needed way down the line