A few archetypes got some new cards to play with, most notably Simorgh, The Agent, Floowandereeze, and Harpies each getting a new card, with some of them even having some old cards in the pack so you can build a deck
He is taken care of by KaibaCorp doctors on the Kaiba's blimp, until Yugi's Duel with Kaiba in the semi-finals, when Tristan drags him to the window to see Yugi's Duel claiming Yugi needs him (and Joey starts regaining consciousness after Yugi summoned his "Red-Eyes Black Dragon" against Kaiba)
Yes, a creature can adapt again if it no longer has any +1/+1 counters on it , regardless of whether it already adapted earlier that game or not
The water club almost gave me nightmares as a kid
One of your opponents Benched Pokmon is chosen at random 3 times
Some abilities add counters (allowing you to save up for the more costly abilities), and others reduce counters