late reply, but i should say that you absolutely can use any parts of sclang in norns engines, including patterns and sequencing. the idea is you make an Engine subclass and there are some very basic structures for accepting commands from lua and sending data to lua. so you could certainly generate callbacks in lua from a Pattern in SC for example.
so you could do all the heavy lifting in your SC engine and just use lua as glue for the hardware UI (screen, knobs.)
that said, using SC for MIDI or OSC interface would maybe a little less friendly for the overall health of the ecosystem - we hope that most external control functionality will be defined in lua and easily customized. but if you just want to port existing supercollider stuff with minimal modification, that is of course doable.
