Ivra posted the skills of the pet dragon. DGDobrev also posted this information in the KBAP Info thread
http://forum.1cpublishing.eu/showthread.php?t=10991
What I missed is a 'quick refence guide' - thingy to plan the upgrades of the pet dragon. Maybe it's useful for someone else.
Note 1: when multiple upgrades are available on the same level, I put the one with the least mana cost first.
Note 2: there's no guarantee that the game will actually offer an upgrade as early as possible.