Gustafsson would be his toughest fight at LHW. His TDD, size, power, speed, length, chin, mobility, and slick boxing would be a real test for Weidman. Despite Gus coming off his first ever TKO loss, he'd be a formidable challenge for Weidman and is also good at scrambling back to the feet (see the Jones fight).
Jones doesn't have the power to really make Weidman worry too much and Weidman's footwork is on a different level than Jones'. Jon would struggle, at least at first, to take Weidman down too. I can practically guarantee it due to Weidman's reflexes, range control and TDD being so damn good.