The levels aren't programmed to be playable. Then there's the chance they aren't even there but they are making it. The extra day would be probably to assure this is not only an Egypt thing. I don't know why they are in the map level selectio, but I can understand why the other 2 aren't here yet.
Because the 25th levels of Pirate Seas and Wild West are technically there, just not accessible(presumably may be unfinished). And the key you still have is a World Key, used to unlock other worlds. (apparently moving from a pre-1.7 to a post-1.7 has your stars turn into completed levels, unlocked worlds are instantly unlocked, and I believe that you are given a World Key(there may be some extra conditions, I believe we both got all stars).)