NRNs can be both Nepali ctzns living abroad for certain time and the former Nepali citizens who now has foreign ctzp.
If you are nrn who hasnt received foreign ctzp then you are a full fledged Nepali and have all the rights.

If you are nrn with foreign ctzp then nrn id card can give u certain benefits but now since nrn ctzp has been approved you have better option.

Nrn ctzp should grant you all the rights except for voting ,political or taking any govt jobs.

Nrna membership, which is a membership to the association has no bearing on the above two, ie, nrn id card or nrn ctzp.