there are no stupid questions ! (and your guesses are all good…)
1/ yes, 5 is a good value. Just for an exeample, if you choose 3, it means you limit the number of users, but want to provide more throughput per user (less sharing)
2/ NH_RH : refer to other older threads in this forum to find some valuable info.
Regarding DL FER : it is not available in NPO, because to be so, it should be reported by the MS… and it is not 🙂 You can use a rxqual threshold = 5, instead of 4, and that would be close enough to reality.
to assess dl fer, only one solution : the drive-test.