1 - For native you have lion_rsm's emulators, they are really good and some people say they are better than the Dingux options. It's really hard to answer that, "better" means something different for different people, but they are fast, have good compatibility and all have the same interface. In Dingux you have also good speeds, good compatiblity and much more options (more emulators of the same system and emulator for systems that doesn't exists in native). I really recommend you to test the different options, some systems are perfect in both OS's, but some will never be (like SNES, EVERY emulator has his limitations).
2 - I guess it's not exactly the same, maybe someone else knows better. There's a subforum for the A330, you may find your answer there.
3 - The final version of OpenDingux will support this, but for now it's impossible.