Can using this mod make my game unwinnable?

You bet! However, for supported mods (see dependencies) the default settings are designed to prevent softlocks. If you use default settings and still get an unwinnable state of recipes, that's a bug and please report it.

What sort of information is useful in bug reports?

Aside from a description of what the problem is, I'd appreciate to know the Factorio version, list of mods and their versions (including those provided by Wube and this mod) and any deviations from default mod settings. This information allows me to reproduce the problem easily and hopefully come up with a solution.

Can I contribute? Fix bugs, make pull requests?

By all means, help is welcome.