Well I think bromine is the best halogen for the 2,5-DiMeO drug molecule. However iodine is a very valuable asset since it is useful for imaging purposes to map this wonderful drug in-vivo.
Really this is the first time I have seen this published anywhere. I would seriosuly consider this an interesting find, though maybe not quite as good as 2c-b but still interesting. A chemistry prof told me bromine is the same size as C6H6. Perhaps a slight exageration but this claim should be put to the test though I doubt it will yield anything that great.
putting astatine in your body is like asking for a plutonium cocktail. also there are only about 1.2 grams of natural astatine on earth (i don't believe anyone has ever isolated a visible quantity).