I am not sure what the various dates are for declaring for the Draft, for returning to school, etc...
Does the NCAA allow a drafted player to return to school?
Assuming he has not signed with an agent?
The best case for the Jets(other than getting Lawrence)would be a huge windfall in a trade down that allows them to still get a QB like Fields or Lance.
There is always the chance that Darnold plays well enough that they feel confident in him and that he costs them the #1 pick anyway.
The giveaway on the jets motives will be whether they fire Gase or not. IF they are gunning for #1 they will keep him, as they could not risk a change juicing up the locker room for a couple of useless wins.