I think you can order 2 of each version when the orders go live on Monday but you should be fine. Might be worth contacting them anyway as they are really quick to respond.
As for the PS4 versions - they sold out in an incredibly short space of time - Vita versions sold out slower for sure though which makes me sorta relieved at only collecting for Vita. Plus its Oddworld, so demand will naturally be greater than for SMRPG. Fingers crossed all goes well on Monday...