I hope the new CBBE work with vanilla skyrim, SE make no fun without SKSE and Sexlab... but it runs so smooth.
No, we won't make it for the old Skyrim. Don't want to give people more reasons not to use SSE and it's too much extra work. Sorry.
Do we know if that's going to break dismemberment for SSE like high vertex count does in FO4?
Skyrim does not have dismemberment. The only thing you can cut off are heads.