New VM design

Looking for some bullet-ed opinions on designing Host, Storage and VM HA and Backup/DR.

1. what to consider
2. avoid
3. look into, etc...
4. know - All sites need to manage VM centrally and not have to connect to each.

So far thinking for the 10 sites, that are pretty much self contained to their local data needs, with a 11 out of state idential locs and 1 corp office(IT out of) the following:

-Three host identical (2 proc, 8 cores apiece)  - local storage(4 VMs(normal FS, DC, SQL box for niche market mgmt software, 1 other VM). Wasn't going to introduce external storage via SAN.  Any good arguments why should!?  

-Approximately - 5TB free after R10 or R50 with HS on local host

-Goal/Need - VM to be configured HA, Backup of VMs.

-For the backups I've been researching Veam, but so far not liking what I'm reading on Veams offering of HA vs backup of vCtr vs vServer. So my DR design needs help, suggestions!?

All sites need to be managed centrally.  What to scale VM product/licensing would be best for that?

Looking forward for food for thought, routes to look into... Thank you experts.