Officially, Oslo does not have any Fv route, please refer to wikipedia.
Oslo og Moskenes kommuner og Svalbard har ingen fylkesveier. ->
Oslo and Moskenes municipalities and Svalbard have no county roads.
Thus, I'd like to keep it as-is.
If Fv4 doesn't officially exist then this is the correct interpretation. This does mean OSM is wrong though (okay that's not really shocking).
Should I also rename the other Ring3 wps since they are concurrent to Rv150?
Nah, I'd leave them. With the ones I commented on those exit numbers very clearly belong to E6 so they need to be marked accordingly. But Rv150 doesn't extend beyond the part of Ring3 that isn't E6. So those exit numbers don't belong to Rv150 and more than they belong to Ring3.
Kinda curious how the exit numbers ended up the way they are though. Did they just decide to start at 50 because they didn't want to restart at 1 or continue E6s numbers? Or did these numbers used to be continuous with something else that was renumbered?
Any further comments before activation?
Nope, activate away.