The controller's plan was to have the C208 land close behind United but on 4L precluding the use of Kilo as an exit without a "hold short".
The controller knows the C208 will likely exit via Echo (or maybe even Delta if wake can be avoided)
To facilitate this plan I see a couple of options:
1 - United is instructed to exit at the end with the landing clearance; By the time they get there the C208 is no factor.
2 - Assuming no traffic close behind United on 4R, United is given the option of Kilo but with an expectation to hold short of 4L.Once United had landed, they could be issued a "hold short 4L".
Without passing on their plan, the controller did not give United the full picture. "You got Kilo?" is a pointless question if the controller doesn't intend to allow them to use it. If they allow them to use it then they either need to cross 4L & 8L as their speed will likely not allow them to hold short.
The chart remark “WIDE BODY AND 4 ENGINE TBJTS LDG ON RY 04R ROLL TO END OF RY, NO LEFT TURN AT TWY K WO APVL.” should have United either planning on the end or being given/seeking approval for a Kilo exit before landing so that there is time enough to plan its use.