There is no simple way of starting icewm-session or it's individual components within the framework of the desktop handling.
[EDIT: Do not use desktop=icewm-session, does not work.]
Of course, I could make an icewm-full extension that simply uses a wrapper named "icewm-full' that invokes icewm-session. That would allow a full icewm to be used by those in cloud mode as well as I could cut out the unused binaries out of the present icewm extension and make it smaller.
I will ponder it.