I fly into Ballina and Lismore a lot and have never had a problem with the frequency. All you have to do is to keep an ear open for calls. Due to the three fields being quite close, and RPT going into two of them, they SHOULD be on the same frequency to help your situational awareness. Yes, Evans Head also but it rearly has not much traffic.
Regarding Casino, the land and terminal building was sold by the Richmond Council. While this Council is not "airfield friendly" I can see that future RPT service to Casino is very unlikely due to the closeness to Lismore. The land was purchased by the Campervan and Motorhome Club...I personally think that it was lucky that they did not want more space as with the Council's record there probably be no airfield at Casino!
I have found no problem with RPT traffic. If you fly with an appreciation of their speed and talk to them, I have found them very polite and helpful. In fact once a bit after I had given a 10 nm call to Ballina, a JetStar came back to me and said they would hold until I landed, recommending a fast straight in approach as there was the mother of all rain storms approaching from the east...I did, and there was!
Only problem I have ever had at Ballina was with a GA school based a bit further north of Ballina, in that one of their aircraft tried to hit me head on in the circuit. After an approperate radio responce drawing their attention to ERSA (and to be honest probably their parentage), their instructor admitted (only after the CFI of local flying school who was in another aircraft, backed me up) they did not have a ERSA with them...and I assume had never read it anyway! At the time, being on the dead side of the field, my attention was more directed to seeing the wing sock to work out whither to turn right or left after joining cross wind instead of looking out for illiterate GA instructors!
I can only think someone is "manufacturing" stories to fit into their own agenda.