Big UGJ Question

As long as the current isnt too powerful then yes. I'd say most cichlids when grown are able to even if they are digging right into it like below the jet...

The jets are only focused in certain areas anyways so for the most part the answer to your question is yes.

Yes, most definately. Cichlids will almost always dig no matter what, say, they may not dig in front of the jet, but they could around it, and expose the pipe, and out a little bit in front of the jet. Cichlids are amazing excavators that take on landscaping projects of their own... :roll:
Of course, not asking you're opinion first.
But you can dye the UGJ piping black.