Thank you both for the very helpful answers. My main concern on the crack in the front veneer was just how difficult it would be to fill vs if it should be replaced. I'm absolutely in love with the spalting in the maple, so I didn't want to replace it if unnecessary. I will work on finding the right color of filler to match that section, luckily I've got plenty of time as I'm not ready to truly start on this project yet.
That's good to know about the fretboard, I will work on cleaning that up and see how it looks after that!
Simon, on your question about painting, it's kind of a long answer but unfortunately I have no space or room to spray a guitar. I could be very mistaken on the concept of painting a guitar, but I've always taken that to mean spraying a guitar with either a rattle can or spray gun. I'm working on a project in which I'm hand painting a guitar, but it's slow work that I'm not sure will pan out in the end. My plan was to use Wudtone's Black Magic Woman stain on the back and sides to have a transparent black coat and show the grain in the maple. If there's another way to paint that I've completely overlooked I'm definitely open to the idea, I just have more experience with the Wudtone type stain. I was concerned about how roughly cut that neck joint was, and those dark lines on the corners of the sides, but if they aren't a big issue I can find a way to work around them.
I appreciate the feedback on the nut too. I found an interesting looking one on theviolinbass.com, I just need to figure out if the measurements match up first: