A few more details of your tank size and numbers would be good. What sort of set up are you looking for?
Examples of fish that seem on the whole to be successfully kept with Frontosas would be Alto Calvus, Alto Compressiceps, various Synodontis catfish, Bristlenose catifsh, Leilupi, and as you suggested Blue Dolphins. Others will have other examples as well. There are however examples of Fronts not getting on with certain Blue Dolphins and Calvus for example, so nothing is certain.
Personally I would keep a colony of around 10 Frontosa, 2 or 3 Bristlenose and maybe a pair of Calvus. The focus should be on the Fronts IMO.