D League players sign contracts with the League, not the team, and the new rules only allow NBA teams to dictate which D-League teams players are sent to, so NBA teams can't offer players an incentive.
Journeymen playing in the D League rather than overseas get less money now, but get to be closer to their families and are available to sign 10-day contracts.
A team doesn't have to maintain the maximum size roster, only the minimum of 13.
I don't think it makes sense to allow teams to cut a player later in the season.