1. I can replace the transceiver on the dead port on the Qlogic card while the host still has other VMs running? I have done it in the past, but while the host was in Maint mode. For reasons I wont go into here, I can't Vmotion anything off just yet
If your HBA card support this (I believe it supports) you can replace the SFP without any problem, since this is already dead then will no make any difference.
2. If #1 is true, there should be no interruption to storage or data corruption once the path comes back up? I am doing round robin.
No, VMware multipath will handle this without problems.