I don’t mean to be that guy; if you have good reasons for full virtualization by all means go for it. Have you considered LXC (Linux Containers) though? Given the memory constrains on these devices it might make more sense. You can easily pass kernel device nodes, and even physical network interfaces thru to the containers.
Now if you want to run a mixture of Linux and BSD or something that won’t work but you can make just about any mixture of Linux distributions run.