Copy-only as the routine backup
It sounds like you've done your homework to a large degree.  Clearly you're aware of the log chain implications for COPY_ONLY backups.  My advice to you would be to ensure you have a clearly though-out and tested restore plan.

Without having tested your disaster recovery plan, you can never be certain it will work, and therefore it's not a plan.  

If you can do standard, i.e. not COPY_ONLY backups, then do them.  I might consider doing standard FULL backups on the primary node every so often just because you can never have too many backups.