It's a quick and dirty library which gets the job done for my project and I thought of sharing it...True, it could use with some improvements, but I ain't going to spend any more time on it now.Maybe in future. I focused on my specific needs instead of a more larger view so that's way the issues you highlighted above are present.
1.This is correct, a font is better than char*. Maybe I'll change it.
2.This issue has two faces really. I mean, yeah, to render a string could be useful. Probably will change that too.
3.I need the screen surface to pass parameters to SDL_CreateRGBSurface function. And was useful for debugging.