Can Monitor Nodes be VMs?

Thanks, so basically we can those OSD nodes as both storage and monitor nodes?
Yes, the MON services don’t require many resources and be co-located with OSDs, although that might not be the supported or desired way, but it surely is possible.

And about the network ports, is it ok to use 1GbE interfaces for management and ILO or there will be issues?
For iLO and the management network 1GbE is sufficient, also for the public network if you have it separated from the cluster network.