dap usually ties to dashboard_engine, but did you actually mean data_engine?
As far as I know, dap (and dashboard_engine) are both deprecated, so I guess you should have 0 (unless you are using some of the deprecated functionality).
When it comes to data_engine, it should support running more than one, but we are just running one active at a time, and use HA probe to activate it on the passive hub should it take over. data_engine probably shouldn't be deployed to all hubs (as a rule of thumb at least, but there is always exceptions).