Additional ways to clue you in to some special, often valuable cards: Secret rares have a collector number higher than the total # of cards (supposedly) printed in that set, for instance "65/64" or "110/105." Secret rares can range anywhere from a couple of dollars to hundreds of dollars
Any attempt to recolour would be considered an alteration by grading companies
I'm not against using it to self mill to get a win with Jace, which sounds like it'd be a VERY good win con combined with Archmage Emeritus, Thousand-Year Storm and Veyran, Voice of Duality, or to fill the graveyard for me to cheat something out with Narset, but I wouldn't really consider that ideal in that circumstance because the ideal situation (in my mind, at least) is I'm using Narset to cast something twice
Its important to remember that this is a persistent effect without a specific owner, so it will continue for the remainder of the game, even if Vadriks owner leaves the game