hey guys, I'm getting my hands on a Fender Highway 1 Strat body, which is routed for a HSS configuration. I want to drop in 3 single coils instead, and i'm pretty sure this is possible, but i wanted to double check before spending the money.

It sure is, just get a new pickguard that's routed for SSS.
Personally, I'd just leave the humbucker in the bridge for a bit of versatility.
"Everybody, one day will die and be forgotten. Act and behave in a way that will make life interesting and fun. Find a passion, form relationships, don't be afraid to get out there and fuck what everyone else thinks."