holy wow fusebox, that is an impressive lineup you got there!
I gathered this: Developers make the DSP core functionality, provide vector graphics and send that to Propellerheads who compile it for integration in the new Rack Extension format. That way it will work in future Versions. Then you can buy it or get it for free in the Reason shop. u-he said that they want to provide discount for VST buyers, but the Rack Extensions will be a bit cheaper than the VSTs. There will be 30 day trials for all REs as well and they are cross platform.
It's sandboxed, so it can't crash Reason, has full copy paste / undo functionality and integrate the cables, Audio as well as CV!