I think the question of pork and alcohol could be solved by having the slavs adopt a different, more environmentally suitable interpretation of sharia law. The second line in this verse may be useful as "being forced to eat it" could be related to the living environment:
He has forbidden you only the Maytah (dead animals), and blood, and the flesh of swine, and that which is slaughtered as a sacrifice for others than Allaah (or has been slaughtered for idols, on which Allaah’s Name has not been mentioned while slaughtering). But if one is forced by necessity without willful disobedience nor transgressing due limits, then there is no sin on him. Truly, Allaah is Oft-Forgiving, Most Merciful
[al-Baqarah 2:173]
I mean, sure, they'd be seen as kafir by their brethren south in the middle east, but it's common for religious taboos to be discarded or created depending on the situation of the people who follow them.