assuming you have lat registers on your pic chip , porte is not equal to late they are separate registers . check the memory map of your chip.
pbp has no glcd native functions, whether your "glcd library" uses late is completely dependent on how the library was written .
if you define your "data bus" as porte I would expect it will not use lat regs (that would probably require two defines , one for each direction)
and lastly rmw has no impact at all when you are writing to the whole port