VM Project

So, it looks like we are going to:

Buy:
1. 2x new hosts,
2. NAS (iomega),
3. upgrade our existing host (disks and RAM)
4. win 2008
5. exchange 2010

we already have:
1. veeam
2. essenatials

Plan:
1. create AD DC VM
2. migrate all physical to the 2x new hosts (load balance the resources)
3. migrate vm's from current host to other 2x hosts - down and decommission the existing host upgrade hardware and move to DR site - do the same here and convert p-v.
4. Use NAS as repository for veeam backups.
5. migrate AD and exchange.

questions:
1. is there any VM's i.e. veeam, vsphere, DC etc that will be best left on a physical box?
2. once all are migrated from P-V we plan to migrate from 2003 to 2008 and Exchange 2007-2010 - is there anything glaring that i have missed?
3. we also plan to use veeam for exchange and SQL backup to NAS & also (option) to continue with Backup Exec 2010 for exchange backups to disk (NAS) - daily, weekly and monthly.  Is this worthwhile?
4. Do i need 3 veeam licences per host?  
5. Can veeam replication be used locally between the 2x live hosts or is it best to simply use the backups on the NAS should a host fail or be offlien for maintenance?
6. We also have 2x DC's with Exchange and SQL.  Is it reccomended to split these roles?
7. PLan to use veeam for replication of live hosts to DR.  Again what needs to be done here?

Thanks