Why the different harness types for front vs rear if all of the signals are the same? Harness types should be consistent through harness connectors and ports. If you need to differentiate harnesses of the same type by function that can be done by the port name or other annotations. Setting all of your ports and harness connectors to the same "LED RGB" harness type will get rid of the multiple harness types warning.
The "Net has multiple names" warning is basically inevitable with multisheet designs especially with harnesses or busses in the mix, I just turn that warning off since it's just noise and doesn't really help with validating connectivity.
As for the names the nets end up with after compilation, that depends on your project configuration. Unfortunately there are a ton of possible combinations of options and it's not always clear how they will interact with each other or with harnesses, so if you want those nets to end up with different compiled names it will probably just take some trial and error.
As a more general note, are those really long net names in the net labels really necessary? One of the benefits of multisheet design (especially with harnesses) is that you don't have to create long, specific net names like that, but instead can use shorter local net labels within sheets and allow the compiler to resolve them to suitable project-wide names based on your project settings.