idk about 'experimenting with' considering thats just what they got with the early mig-21s. iirc the front hinging design on the mig-21 was originally intended to help shield the pilot during supersonic ejection -- something the us was also worried about during the early days of supersonic aircraft. the us went with crew capsules until supersonic ejection incidents showed that they were survivable without extensive protective measures.The Chinese have been experimenting with front-opening canopies since the J-7 days.
i can't think of any other chinese aircraft that subsequently used front hinging canopy, even the later marks of the j-7 that were closer to the original f-13 than the mf/bis switched to rear hinge.
anyways the intents behind front hinge canopy of the mig-21f-13 and the j-35 i expect to be completely unrelated