Right now, apparently you need a certain island level to change certain biomes such as 'Open Sky' (End), I suggest this be removed because I think it does not detect modded items including chiseled blocks. Also, I feel as though this island level thing is pretty useless.
I vote for option e) Remove the ability to change island biome completely. Reason: This pack is about bees and especially in the case of end bees the modpack creator wants you to come up with ideas how to get them working in the biomes you have available. Just changing the biome to whatever you need defeats the purpose of the pack.
Thanks. I think the original map is on a Plains Biome, but other biomes are close. I might have to check that out. On our server a lot of people seem to start on ocean biomes. Not sure. Is there a standard setting for sky block maps?