What kind of RTO/RPO are you trying to achieve? What kind of disasters are you trying to protect against? Localized, regional? Is your redundant storage in the same location as your primary storage?
If you have a backup of the VM, what's the point of backing up the LUN or datastore? Serious question, as I've never seen it suggested. I can understand backing up the array configs, but the data itself seems overly redundant if I already have another appropriate backup plan in place.
Replication is what's always been drilled into my head, but if my hot/warm site is in the same location as my primary site, then what's the point? Obviously, that depends on what I'm trying to protect against, how much data loss we can tolerate and how quickly we want to recover. These are important questions that will point you in the right direction. If you want very little recovery time, then a hotsite at a co-location might be something you want to look at. There's a bit of setup and additional overhead involved with that.