Pick a class that is cool to you, don't worry about power. Your character will develop, and end up with special little strategies no matter what. I have a lvl 14 Kensai, dual wielding, and though I forsook the more powerful kensai/mage, she is still a wicked blademistress and fun to rp.

Where did this myth of Edwin being better any PC mage come from?

Its blatantly false.

I would preserve my own character, simply because it feels more fluid when you have the same stats/character and you don't have to spend 20 minutes rolling the dice.

Not really, Edwin has a most remarkable amulet. In exchange for the Amulet of Power, he gets an additional 2 spell slots per spell level. This gives Edwin an obscence amount of spells, and spells is what a Mage is all about.