Cool, cheers.
Giant danios would be OK, but with those dimensions I wouldent get too many, like 4 or 5 would be fine.
Bare in mind however that giant danios are very active, and in that that size of tank any slow moving fish like angelfish and bettas would be very inlikely to do well with them (rams are OK because they mainly stay near the bottom, and like going in and out plants and things). Tiny tetras like neons probably wouldn't even fare too well. So they would limit stocking a bit.
Personally I'd just get 6-12 regular zebra danios, or any of the more fancy small danios/rasboras/tetras.
Could add some corydoras or other small bottom dwellers later too, when the tanks a little more established (give it a few months).