Yes, you can use SK to do that, but then you are playing with fire. Don't be surprised if you get burned (massive bugs, corrupted save files, etc.).

no

The Kensai-Mage only needs 93 stat points to be optimum... 5 x 18 and 3 in Charisma. As it was pointed out, the ring of human influence is found so early in the game a naturally high charisma isn't required.

If you play through BG 1, these stats are even better. 4 x 19, 22 Wisdom and 4 (at a minimum) Charisma. You could use the charisma as an excuse for the character soloing :D

Have fun with it.