1. I usually take mental clarity first, as I find levitation and reflection is not required early on. I am not taking ranged damage (LB 2 outranges everything), jumping in pits, or needing to avoid terrain (just don't stand on the water, it's easy :P). As long as I have enough MP to LB everything, nothing else matters. I almost put it as take mental clarity 1/2 first, then take shroud, as I do think its stronger that way.
2. Disengage 2/Lunge 1 take 12 dex. Lunge 2 takes 14 dex. Even if you get 1 additional dex, the earliest you can get Lunge 2 is lvl 6. No extra attributes and it is lvl 9. What will you do with the talent points before that? Take disengage 2 at lvl 3, then lunge 1 at lvl 4. This won't delay lunge 2 at all.
The difference between having disengage 2 or not early game is massive. The game plays so much faster when you are keeping your SP on every kill. Disengage 2 is also the safer option, if you get in a dangerous situation, being able to disengage and step back, keeping pace with fast enemies and getting the maximum amount of SP is what you want.
I left the duelist talents early, as I don't use strafe attack enough to know exactly where it fits. I probably could have said: Disengage 2, Lunge 1/2, Dash Attack.
3. I find discord 2 is a massive upgrade. It is a 33% dmg increase, per attack, which by itself is strong. It also has very positive interaction changes, like reducing the number of hits most early backline enemies need to die by 1 (saving you both a turn, and from being damaged at all in many situations). What else can an enchanter take early?