Hi,
There are a couple of things I don't understand from your infrastructure but from whay you explain, your admission policy will not allow the VMs to power on.
My suggestion is to change from "3 nodes" to "33%". 3 nodes is excesive I think when general good practices are about having an infrastructure of n+1 only.
DRS/DPM works in conjunction with HA, so yes, DRS/DPM recomendations take into account HA admission policy.
Regards,
elgreco81