Do you guys think that a stanles steel solid shaft would work or would there be big issues. the reason i wanna go stainles is because ill be running my boat in salt water

I would/always use a stainless steel shaft no matter what kind of water I would be running in. If you were using a plain steel shaft and any water or moisture would get to it, it would rust. If left long enough the rust would build up to a point where the shaft won't turn anymore.

Running in saltwater does require you to do a tear down every so often to clean and lube things up.