On "... my other guests wouldn't be able to communicate with each other ..." specifically, please make sure that you turn off firewall on all guests.
On "... services such as DHCP and DNS may conflict with another DHCP and DNS service on another network ...", I'm not sure if you have set up a DC among all guests or decide to use DHCP for them. I have to say that I set up my virtual network among VMs with a domain/DC with static IPs on all "applicable" guests, while I have other guests using DHCP since they don't belong to that domain. On my DC, I've enabled DNS so that all other VMs on the domain can use it. So, if you have a DC assigned, I'd suggest you try static IPs first.
About static IPs, you can use anything, but I'd suggest not to use 192.168.x.2, if your NAT's subnet IP is 192.168.x.0, because 192.168.x.2 is its default gateway.
I've not yet tried to make any kine of connection between my host, which is on an intranet/VPN all the times, and guests on the virtual network/domain. But, I'd think that, if there's anything blocking the communication, it's probably on my DC/guests.
