The Tera Burning event is part of the Black Mage update. The update itself will start on November 14. We have not yet been told when Tera Burning will begin.
Keep your eyes on the website. The Tera Burning start date might appear in the Update Highlights if we get them (usually happens about a week before the update itself). It will definitely be listed in the v200 Black Mage Update Notes, which will be posted November 14 or possibly the day before. And it will also be visible in the in-game Event tab after the November 14 game update maintenance.
You cannot apply skills to Esel because it is an event pet that cannot be revived.
Contact Customer Support for a refund, since none of this information is given either in-game (the pet's description or the skills' descriptions) or on the website (the "Maplestory 2 Hot Week" event notice).
You might need to refresh the page a few times. Then you will see that the first frame (where the teaser video used to be) now has Cygnus missions, and between the frames and the countdown is a "base" you need to build.
It is definitely intended.
We had one DMT where it was not possible to cube sealed items, much to everyone's surprise, and Nexon reverted that change and re-ran DMT a week later.
As for what the desirable functionality is - personally I think we need two separate kinds of item guards.
One kind that only prevents the item from being lost (so no drop, sell, trade, or use any form of enhancement that can destroy the item),
and another kind that also prevents the item from being modified (so, in addition to the above, also no cube, flame, or non-destructive scrolls and enhancements).
