The Gift Drop can only show up to 20 items.
Because Nexon gave us 15 separate 2x drop coupons, everything else got pushed down and can't be viewed, but is still there.
To see those items you will need to claim some of the items you can see, and then relog (or change channel, or go into and out of cash shop) to refresh the Gift Drop.
Increased Cubic Blade and Cubic Chaos Blade drop rate from Elite monsters and boss monsters.
I believe this is what happened:
The KMS Adventure patch increased their drop rate for these items.
GMS drop rate for these and other premium rewards has already been greatly increased (to near 100%, as observed upthread) a while back.
GMS Adventure patch copied the KMS Adventure drop rates, which while "increased" for KMS, are lower than what GMS had.
SavageAce mentioned "Decreased Cubic Blade, Chaos Cubic Blade, and flame drops" in his latest memo, as something Nexon is looking into. Hopefully they will restore our higher drop rates, since the intention was to increase, not reduce them.
Level flames can only be used on items (not item types, but specific items) that already existed before we had flames.
Since your Maple Treasure items are new (you just bought them from the shop), only Powerful and Eternal flames will work on them.
The in-game indication as to whether an item can or can't have level flames applied to it, is the small circle in the top left of the item icon on the tooltip. If it is solid white, the item can only use Powerful and Eternal flames. If it is gray, the item can take leveled flames.