With regards to question 4. You don't have to worry since a lot has pointed out that you can still reach a competent level even with massive mind reading.
I can't vouch for the Ego Draconis part though. I can only vouch for the Flames of Vengeance where I mind read everyone and still managed to reach Level 48.
And... uh... at some point you can reset your skills so don't worry too much about how you spend them. If this is considered a spoiler, my apologies.
About the physical and magical, from my experience, high intelligence and strength will guarantee you to reach 2000+ damage with dual weapons.
About hide in shadows, it depends upon your experience. From my experience, there are instances when your character might be interrupted preventing its use.
