Threads were not created for some of the lower islands. There are threads for some of those levels, though. What level are you looking for? Try searching on the Jewel Mania | Discussions main page, using the Search Forum drop down. Type the level # with quote marks to search, for example: "level 25". If you can't find any help, post a question for the level you need.
I'm not sure what's happening with your challenges. Swiping special jewels together is just as you said--swap one blaster's place with another, etc. Perhaps the challenge has to be done on a particular level-- did you follow the directions exactly? If you're doing everything correctly, perhaps you need to update your game, or delete & reinstall (your progress is saved--don't worry!) Good luck!