6. The earliest and easiest dragon to kill to get the medal is on a ship patroling Scarlet Island. It's an Emerald Green dragon and the hero usualy has 4 stacks of 30 each pirates on impossible. He usually casts Fire Arrow, Book of Evil and sometimes Poison Skull. He's not too hard to beat, i usually take him out on the way back from sneaking! I also wait to see what he's going to cast each round before i use my pet dragon as the Evil Book only has 100 def so its kung fu kick is a good way of taking it out.

8.
I tried with a Mage on impossible. I already had the Dragon Medal lev 1 and Exp lev 2 for the pet dragon on the Might Tree. I used 1 Archmage (for protection), 1 Inquistor (for rage) and 1 Royal Griffin (for opening chests) to clean out Debir. Managed to get the pet dragon up to Lev 7 and Lev 1 of the Guardian Medal by the time i finished there, so yes it's definitely a good thing to do.