Define "completed". Do you mean "I beat Bowser in World 8!" or "I beat the True Final Boss of World 0 and collected all the star coins!"

Porting SMB3mix to SMW is an oxymoron. It would be more like a remake to the ladder's engine. SMW has been broken up into little pieces dozens of times to the point that such a remake could be done quickly if you knew asm and Lunar Magic (that's what it's called btw), but it wouldn't be the same experience. If somebody were to crack open the Super Mario All Stars SMB3 and port SMB3Mix to there, THAT would be impressive. "Porting" SMB3Mix to SMW...not so much.