I think KVDU has 2nd adjacent KWMZ blocking it from moving south. Back in the early 2000s there was an application to move 104.1 closer to NOLA on a 1500 foot tower. I think WZRH would have the easier time. It could move to the master antenna on the west bank and still put a 60dbu into Laplace.
Sort of. WZRH appears to be less constrained by adjacent signals, but in order to get a 70 dBu to Laplace it would need to be at least a C1 from the west bank, or possibly a C0. I guess they could "backfill" Laplace with another station and then pick some new community for WZRH, but that is now a multi-step multi station process that will take a long time and is less definite.
KVDU can't move to the tower farm, but it could move much closer to the population in St. Charles Parrish or the northern part of Jefferson, the problem though is that i am not sure there are any suitable existing structures in the area.
We regards to KWMZ and KVDU the concern is just keeping one stations 100 dBu outside of the others 60 dBu. So if you pull up the map of KWMZ, any potential KVDU can't be inside that circle or within a few miles outside of it.