In general, it's absolutely no problem to run multiple SCSI adapters in a single Amiga. I'm pretty sure the GVP ROM does not work with an '060 - early ROM versions have those issues as I recall. The incompatibility makes the machine crash when both '060 and GVP SCSI are present. You could try deactivating the caches in early startup, but that's only with Kickstart 3+.
If you want the GVP to work, you'll need to update the ROM. Otoh, that doesn't really have a point as the Blizzard's SCSI is way faster.
