That looks right. I do see a problem with that inheritance tree. T-mod implies a level of immunity, however FreeVIP, VIP, Nebula, and Galactic can all target them. ULX only really supports inheritance in a linear tree (each group is inherited by zero or only one other group), whereas you have 5 groups inheriting from user. If that is what you want, that's okay and it will work properly, however you may run into issues if you decide you want it the other way, because it's not as easy as just changing the "can_target" (however changing inheritances isn't too hard)
But your can_targets are correct. Essentially you want any given rank's can_target to be "!%" and then whatever rank is immediately above it. Having FreeVIP's can_target as "!%VIP" wouldn't work as expected due to them having the same level on the inheritance tree. If FreeVIP's can_target is !%VIP, users in the FreeVIP group wouldn't be able to target anyone else in their group (or, IIRC, themselves). This is where a linear tree comes into place. If VIP inherited from FreeVIP (which inherits from user), having FreeVIP's can_target as !%VIP would work as expected.