The best auto-retopologizer is Quad Remesher, which is the same as ZBrush ZRemesher. Quad Remesher is available as a Blender add-on. The price for indie artists is very reasonable. See this thread for more info.
I haven’t really dug into 3D-Coat’s UV unwrapping tools, but I do know that it’s got some of the best tools for manual retopology and texturing (PBR texture painting, smart materials and more). And as I mentioned 3D-Coat’s Autopo comes close to Quad Remesher / ZRemesher. So it’s definitely worth considering for these purposes.
I don’t know if there’s a trial version. I’d expect so. In that case, I’d advise you to try before you buy.