any should work fine.
i haven't built with a CMMG LPK in a long long time. i have been running DPMS and colt surplus stuff after the proper de-mill of course.
of all the lowers i have assembled in the last few years i only had one that had a rough/gritty trigger and that was a CMMG---
i put a colt hammer in that lower with the CMMG trigger and now it is fine. then i used that CMMG hammer in a cav arms plastic lower and it seems fine.
it helps to have a few spares to swap around sometimes.