Don't disagree, any bid they choose will affect the Broncos/Titans in some way or another.
Well out of the current or known potential bids atm, say a Ipswich/logan NRL club would affect the Titans more than the Dolphins. From a geographical/catchment perspective Dolphins would represent the bid furthest from Titans catchment. In the same token a Bombers bid would be city central exactly as the Broncos. Firehawks could have a point of difference from the Broncos if they go along the representing "southside" angle.
Catchments don't mean shit anymore, and haven't for decades.
If whoever gets the license comes along with money and/or with better opportunities they'll suck some of the talent from their neighbours catchments at a young age. The vast majority of sponsors will go with the team that they can afford and think will get them the most exposure for their buck. The vast majority of corporates will back the team they can afford and has the most prestige.
Basically no matter whom gets the license (if there even is a license to get), they'll all effectively be competing in the same market in most regards, and how close, or far away, they are from each other in said market will have little to no impact on that competition in most regards (the only major exception being fans).
So at the end of the day Dolphins, Firehawks, Bombers, etc, it doesn't matter, any of them will directly compete with both the Broncos and Titans locally and the other clubs on the national stage.