I'm not sure of advantages of mixing Marvel Mystery Oil in a two stroke using marine engine specific oil. I personally use MMO in my airplane and occasionally use it in the mowers and such. I believe MMO's strength is in 4 stroke engines lubricating the valve train and pistons. One of my airplane owner buddies says of the Continental 0-200 engine, "There are two kinds of owners, those that have had stuck valves and those that use MMO." LOL Personally I wouldn't run MMO in my skis and they are all two strokes. In a 4 stroke??? ... Hmmmm I might be tempted.
From what I understand the Military used MMO extensively during World War II on the aircraft. As I mentioned I think it is good for lubricating and cleaning the top end of the engine (lots of moving parts in 4 strokes up there). It works very well on aircraft engines many of which were designed around that time frame. For me, on the two stroke oil injected engines..... especially on new engines I definitely would not use it. The proper recommended oil is exactly what you should use and all you need.. Don't mess up your new engines with snake oil. It'd be better to run some premix in the fuel.
Why the hell would you want to? It's 1940's tech. If you don't know... it's just hydraulic fluid. (old ATF) It's corrosive, and hard on everything. But back in the day... with no emissions, and leaded fuel... it would strip junk out of carbs, and remove carbon from intake valve. It has no business in any modern engine... and it REALLY has no business being used in a 2-stroke.
The only thing that should be used in a Rotax 2-stroke is, good fuel, API-tc oil... and some fuel stabilizer. (if ethanol is a concern)
My Cessna Aerobat Engine LIKEs it. but I believe the first versions of that engine was in the late 1940s. The certification process does not allow for any changes at all but it sure would be nice to have a more modern engine and more Horsepower, lighter weight, and better economy. Oh well... that is another matter. LOL The 787 has more HP than my plane but I doubt you could run the 787 Wide open for 2000 hours over 20 years.
Back in the day when all the new additives came out... Slick50, graphite, and all that, my friend used to say, You put oil where the oil goes and gas where the gas goes and it's suppose to run. LOL