Well, I haven't played any of the Shantae games, but based on what I remember of them... you could probably make a decent one using Super Mario World as a base and using things like custom level, player and enemy ExGFX and music and whatever else.
The advantages of doing this (over hacking another game or trying it homebrew would be):
1. The engine is pretty dependable, and very well documented.
2. The tools available make editing levels and things much easier than they would be otherwise. Lunar Magic, AddMusic, Sprite Tool, Block Tool, Asar... those types of programs make it a lot easier to add custom resources into the game than it would be if you worked off another title or from scratch.
3. SMW Central exists. ROM hacking is often pretty tricky otherwise, since finding help is an absolute pain on more general sites. With SMW hacking, you both have a ton of pre made resources to fall back on if need be and a community that can help you out when you mess things up (like you inevitably will if you're new to ROM hacking).
As for whether it's easier or will give satisfying results... well, I'm coding a pretty extensive SMW game mod at the moment, and the end result is something that looks and feels like its on its on the Game Boy Advance or later. You can do a serious amount of stuff with the engine and its tools, even without delving into hardcore ASM programming or MSU1 functionality:https://www.youtube.com/watch?v=Lcg773BEILAhttp://www.smwcentral.net/?p=viewthread&t=58407https://www.youtube.com/watch?v=ffilTZOK47g
And even more if you are a ridiculously good programmer:https://www.youtube.com/watch?v=z4hf3rLPpGMhttps://www.youtube.com/watch?v=KgxlTDeyGng
If you ask me, you should probably consider SMW if your plan is to make a SNES era 2D platformer/hack and don't need a really specific bunch of requirements like some sort of unique weapons system crossed with level ups and magic. It's a lot more versatile than editing just about any other SNES 2D platformer, and saves a lot of wheel reinventing compared to trying to figure out every single inner working of the SNES and starting from scratch.
But that's just my opinion.
As for donations... eh not a good idea. Bringing money into the equation is just asking for disaster if the lawyers come calling.