It’s limited what you can do until he plays varsity, pretty much just camps and like I said above get a rep.
If he really wants to get some awareness from the BYU coaches specifically I’d get Will Snowden involved, and the nice thing is Will has contacts and ins with all of those schools you mentioned. Those were a lot of the schools that recruited my son and Will is the one that got him onto their boards and in their minds.
It’s worth it.