So here is a quick explanation on how Salary cap works and where KC is.
1) in the offseason, the top 51 contracts (by Dollar amount) count against the Cap. Dead money from past contracts also counts (so Maclin has 4.8M and Smith 3.6M and a few others) KC has 16.5M in dead money for this year
2) You also have a rollover cap from the previous year. This is money you did not use or go over the previous year cap. The 2018 Salary Cap is 177.2M and KC has 2.6M in rollover (so 179.8M)
3) our current top 51 contracts was at 152.7M. So you want to be a little under the 179.8 max, so KC probably has roughly 24M they are under
4) The signings of Watkins, Hitchens and Anthony Sherman will go on the books shortly. These 3 contracts will knock current contract #49-51 off the Top 51. 49 50 and 51 are counting about 1.5M right now against the cap
5) we don't know right now what these 3 new signings will count against the 2018 Cap. Should know sometime soon. Of course if the Chiefs made any more cuts, they could even have more money off the Cap (as long as that player is among the Top 51 contracts)
6) Lastly, the draft picks for the upcoming 2018 draft. The Chiefs top 4 picks (2nd 3rd 3rd 4th) will cost about 2.9M against the cap. Those 4 will knock off the "then current #48-51 contracts off the Top 51". So basically when they draft and sign those 4 draftees, it will cost us about $700,000 against the cap.
The Chiefs 6th and 7th round picks will not be among the Top 51, so they won't count against the Cap here in the offseason