Self serving and concerning lvl9 only, but teleport options only gives you the option to teleport to the area you're in, not to any other previously marked. I tried it in various places.
Are you completely sure? There are a lot more "regions" now.
Ah, no, my bad. There's one huge central region, but the perepheric ones are isolated. Working fine. Might want to put islands on a same region, for island hoping travel agencies ;)
I'm not sure that would make sense. Teleport should have significant limitations in terms of distance you can go and so on.