Not understanding your question, at all. Can you clairify what guidance you are looking for???
Does any shops offer a build your own type of lower parts kits for AR rifles/pistols? I was on spikes getting most of it but they don’t offer a mag release just a ambi one.
Fulton armory sells individual parts. So does Brownells. White Oak Armory, JP, LWRC, Spikes, and some other quality companies sells a triggerless LPK. If you google “lpk no trigger” you’ll get lots of results for small parts kits without the trigger. Some come without grips as well.
You could also go to USDS in Indy. I know they have small parts.
I bought a red barn armory kit once.....never again. Worst garbage I’ve ever installed. Had to replace the mag catch with a quality mil-spec and pretty much every other part either needed modified or just felt ****ty. It wasn’t a bad lower either. Once I installed BCM parts, it functioned correctly. Lesson learned.