As for the top down veiw that is a simple matter of camera placement and not hard to do plus with a top down (birdeye) cam you don't have to worry about collision. Y would you want to make this a 2d game when you could do it in 3d and there is a lot of referance work already done on this type of project? This type of project using all flat 2d images will invovle a lot of code to swap bmaps during the game... I recommend since you bought a 3d engine ' you make a 3d world... you can still have a cartoon effect by using cartoon like textures. Also a RPG is a big project with lots of inventory menus and and combat code.. You might want to think about starting smaller or joining one of the teams that is already working on a RPG...

My two cents
Malice