If they decide that they are set at tackle and don't require one, your proposed trade with KC is the way to go. You could probably pick up a starting TE, a starting G, a C (at least the backup to Gates), a 3rd corner, a LB and a receiving back with those 6 picks - need to take advantage that our positions of need are also the deepest in this draft (outside of off ball LB)
You would then have the 5, the 6s and the 7. Can grab the 3rd QB and backup buffalo nickel. Could also choose from a kicker to compete with Slye, an extra LB, a developmental EDGE, a return man, etc with those final 2 picks.
The second order effect is that it allows you to then release Logan Thomas and Roullier to open up a bit more cap space this offseason