I put Johnson and Kupp at the top with Littleton 3rd. And 3rd mainly just due to the position and ability to replace that spot easier. Johnson and Kupp are on the cusp of being Pro Bowl players. Johnson and Rapp could become the best safety duo in the league for years to come. Not sure Littleton ever would become a Pro Bowler but he's one of those guys that is not great at anything but is good at everything.
I think Edwards was drafted this year with an eye on starting at 2020 at either LG (should Noteboom slide to LT) or RG (replacing Blythe).