If you don't mind jams, the first four up there have been done! Metropolis Zone and Chemical Plant Zone were done by Quiversee here: http://mabibeats.com/8-person-ensembles/videogame/sonic-2-metropolis-zone-r27/ & http://mabibeats.com/6-person-ensembles/videogame/sonic-2-chemical-plant-zone-r16/, and I just finished up a Marble Zone here: http://mabibeats.com/3-person-ensembles/videogame/sonic-the-hedgehog-marble-zone-r107/ .
Edit: And finally, here's Star Light Zone: http://mabibeats.com/2-person-ensembles/videogame/sonic-the-hedgehog-star-light-zone-r272/
The only thing I can think of to comment on is that while I can hear the Lute just fine, I can't hear the Mandolin very well (I barely noticed it, if it was there at all). I may have just missed it by oversight, but yeah. Either way, very well done!
Welcome! I can definitely see where you're coming from. Most of what I learned was from trial and error with a little info here and there. But while MML and 3MLE may seem a little intimidating at first for some, you can definitely get more experience with some practice!
And if you need any advice, feel free to ask the people around here. They're pretty nice and helpful, and I'm sure they'd be happy to help out with questions and whatnot!