That DK94 project is really great.
DK masters edition would use the original jumpman sprite, but you would have some of the moves from the Mario vs DK series. You would get a triple jump where the second and third jumps go increasingly higher by jumping three times in quick succession while pushing up on the joystick. Also you can get to the second jump height by facing backwards quickly and doing a back jump while holding up. By pushing up while doing the new jumps means that all regular jumps and moves will still be executable. Just don't push up on the joystick while doing them.
This would mean you can do things like if you are at the end of a girder on a barrel board, you can backjump to the girder above, bypassing the ladder.
You also would get a handstand, you can walk on your hands slowly, and do a handspring for 2nd height jump. While hand standing, you can 'kick' wild barrels and springs.
Mario vs DK also gives you the ability to duck and to grab objects and throw them, but I don't see the use unless there are added enemies. Maybe a slide would be cool by running then pushing down. It would look cool, but I can't think of any purpose for it though.
Small changes to the boards would have to be made, for instance raising the final platform on the elevator stage so you cant just high jump to it, to keep it challenging.
Also I would make the boards go higher, meaning the second barrel board would be two barrel boards high, and the third elevator would be three boards high. Theres lots of room for design creativity there, but I would try to keep the board designs close to the original. Boards go higher until max difficulty. Bonus timers would need to be lengthened accordingly.
The 4 DKjr boards would make an appearance at some point, but you would still control Mario with all his abilities plus he could climb vines just like junior.
And of course the coolest move, throwing the hammer in the air, and catching it after climbing up to the next girder.