I am assuming only trading 2 of those 3 at the most because most people won't do a 3 for 1. So if you go with two I would say high end RB2 would be your ceiling. Mid level RB2 is what you should expect.
Hunter Henry and Tyrell Williams
I have Kittle and my other WR are Sutton, JuJu, Fitz.
Basically Lockett would be my flex (replacing Hunter Henry or Melvin Gordon who I would usually play in that spot)