I play the following:
Direct bidding over 2D: maintain original meaning and shows diamond stopper (2nt denies Ma)
Pass: Denies diamond stopper. Partner can then double 2D to restart stayman.
Double: would be suggestion for penalty.
I am missing an option in the vote: "all sufficient bids are legal".
If the 2h bid is done on all hands except superaccept-hands, pass to 2sp should also not impose any constraints on partner; as pass is done on a subset of hands that bids 2H.