Can Instrument Approaches be carried out when RVR is not given for the full runway length? (Approach Ban)
To perform an ILS CAT I approach, at least the touchdown zone RVR sensor must be operational. For CAT II, you need the touchdown zone and midfield sensors, and for CAT III you need all three. As per your NOTAM, if only the stopend RVR sensor is out of service, it should be possible to perform CAT I and CAT II approaches (assuming those are available for that runway in the first place).
There are procedures which allow aircrews to perform a CAT I ILS based on meteorological visiblity alone, using a special conversion table to estimate RVR values based on visiblity, but I believe those are company specific.
RVR can also be measured manually, but I am not sure this is actually allowed anymore. It would require someone to physically go to the end of the runway, and then count the number of runway lights visible from the end. Given there is a fixed distance between runway lights, you could then multiply the number of visible lights with the distance between them to get the RVR.
Not sure what the rules are for RNP approaches, but I would imagine they are similar to those regarding ILS.