Is it OK to run the SP8 update on a NW65SP7 that is NOT the MASTER of the
root for my tree, but has a read/write replica? Normally I do the master
first, but if I can I'd rather minimize the risk by doing it on a less
critical server first, then if it doesn't blow up then do the master within
2 days of that.

Note both servers running NW65SP7 with latest patches, and eDir 8.8 SP2 SMP

I know you used to have to always do the master of the root before as eDir
(or NDS) updates were included in the NetWare SP's, but not anymore.