Exchange 2013 Mailbox/CAS Virtualized HA Approach

Hi team,

Here's my situation, I need to have High Availability on the Head Office and have a DR site as well for Exchange 2013. All Servers are to be virtualized. Here's what i have thought so far in implementing;

• HO - 2 x CAS/Mailbox on same box (Virtualized)
  - DAG for Mailbox HA
  - Level 4 HLB for CAS HA (NLB not supported if I'm not mistaken?)

• DR Site - 1 CAS/Mailbox on same box (Virtualized)
  - DAG extended from HO

Any advice on this approach, is this supported, what points should I have a special focus on etc. is much appreciated.

TIA.