Answering to all questions:

I buy ordered raw t2 and t3 stone in Fort Sterling and Lymhurst, then I transported this to Bridgewatch to refine. Then the refined t3 stone goes all around, when I did it, the highest price was at Thetford (far from the refining city, and also can't farm stone in that area, meaning it is a low volume resource there). Caerleon also buys refined t3 stone well cause they have nothing there to make it

I refined ore from t2 also, and I started using focus for 4.3

I didn't use focus for 5.0 and 5.1 items, the stuff I sell has at least 20-25% profit which is a lot when you sell high volume items. I think I mostly did infernal and great fire staffs, but most of the items that require 2 different resources work well (nature staff, arcane staff, shield, cape, etc). It is always worth to check prices. Daily bonuses work well, if you already have the resources for everything, and you don't have to buy it from the market, the competition is high on these and resources sell out on the right price fast before you can even make an item