For #3 though, England isn't going to be enforcing their rule over Iceland anytime soon, since even the Norse didn't really rule Iceland except in name until the 13th century. And then you still have a Norse Iceland and not Anglo-Saxon.
If you want a really late POD, you could have Iceland be even more unprepared for the 1783 Laki eruption. Perhaps the English rule Iceland for one reason or another. With up to half of the population dead (twice as many as in OTL), and a lot of land free, the English settle in Iceland in large numbers and Anglicise the island, although the Icelandic language would never die out, just be pushed to the fringes. To fit the POD, we could still have no Norman invasion and thus technically making an "Anglo-Saxon Iceland". The Laki eruption is actually a nice way to get the final push to make the island Anglo-Saxon in any TL.
If you want a really late POD, you could have Iceland be even more unprepared for the 1783 Laki eruption. Perhaps the English rule Iceland for one reason or another. With up to half of the population dead (twice as many as in OTL), and a lot of land free, the English settle in Iceland in large numbers and Anglicise the island, although the Icelandic language would never die out, just be pushed to the fringes. To fit the POD, we could still have no Norman invasion and thus technically making an "Anglo-Saxon Iceland". The Laki eruption is actually a nice way to get the final push to make the island Anglo-Saxon in any TL.