The US VC and WiiWare games will work on Pal if you use freethewads on them. Also the homebrew emulators should run on all regions as far as im aware. About your other questions im not sure of the answers sorry.
Probally one of my favortie RPG's on the Ds was Luminous Arc . It is just aother FFTactics Game But i found had a compeling story good characters and good voice acting which made me play it till the end.