1) The Orthodox Church does allow re-marriage - you just can't have more than 4 total, whether you lose them by death or divorce.
2) What's in it for Henry? He wants an autonomous, autocephalous church that doesn't to follow the orders of anyone outside England. Well, that's what the various national churches of Orthodoxy are. If he wants 'respectability' of being in a greater church, without interfering orders from outside, it would be a reasonable choice. The theological differences are pretty minor, and Henry would rather be Orthodox than Lutheran, say. (Of course, he got to have his cake and eat it, too, by inventing his own 'English Catholicism'.) As for things like married clergy and services in the 'vernacular', well those were allowed by the Orthodox (although, at the time, the 'vernacular' in all Slavic nations might have been Old Church Slavonic. I don't know when the Russian Orthodox church started using Russian.)
OT3H, from the Orthodox end, the deal is less good. Henry is clearly only going to make minimal concessions, and if they want to vet his priests for properly orthodox (i.e. Orthodox
) theology, Henry's not going to be very happy. And if he DOESN'T let them do it, England would end up with a highly unOrthodox Orthodoxy.
OT4H, the chance to stick it to the Pope, and have an official Orthodox Church in the west, might be too much for the Patriarch of Constantinople, who might get swayed by the politics of it.