Impressive conspiracy theory. It might be my love for Fable, but I don't believe it. I've loved Fable for years now and have been a strong Christian the whole time.
The map: That was most likely based off of the UK. After all, the oldest name for England is 'Albion', and the weather and landscape is based off of England. It even looks like the UK, with England and Wales/Albion mainland, and then all the islands off to the side. I believe the Northern Wastes were based off of Greenland. Theresa: Although she may seem evil, all that she has done she has done to protect. She also can't be Jack of Blades, as he was destroyed (*see 'The Masks'). 666: Congratulations on passing second grade mathematics. What a coincidence. If only Theresa was actually Jack, you may be correct. Evil being easier: Not always true. Take the Attack Orchard Farm/Protect Orchard Farm quests. The guards are harder to kill and the bandits are easier to kill, making the evil quest ultimately harder than the good alternative. The Masks: Jack's two other masks were cast into the vortex, destroying them. The remnant, the one he wore on his face, was held by the Hero of Oakvale and was the reason Jack was able to live on, until he was destroyed again. Although you have the choice to cast away the mask or where it, we see that in the latter games in the franchise that the timeline is based off of the Hero of Oakvale being good, which assumes that the mask was destroyed. Evil Molyneux: I watched the E3 2003 video, and honestly, he looked like any other presenter at E3, not the slightest bit evil.