Take the trait granting the +2 bonus on initiative checks then the trait granting the +4 bonus on Perception skill checks
Whether casting a battlefield control spell, a spell that buffs your allies, or a spell that debuffs your foes, casting that spell first is vitally important to you and your party's survival. But, while you want your initiative result to beat your foes', you can't go first if you fail a Perception skill check, and your foes murder you during the surprise round, so, obviously, the Perception skill—the game's most important and, arguably, best skill—is vital, too. So take those two traits.
By way of comparison, if you've enough Perception that you aren't surprised, and you go first, you shouldn't need to make concentration checks. No matter what, though, don't pick the prestidigitation option—an appropriate ioun stone (cracked orange prism) adds prestidigitation to your spells known or spells prepared for 1,000 gp, and any cloak of the hedge wizard grants prestidigitation usable at will for 2,500 gp (yet, oddly, a page of spell knowledge can't help at all).