We as tribe do not need _sqllite. As it was said, all mentioned DLLs are either part of official Python3 installation or part of potentially missing CRT for Windows. I do not know why Python3 installation need sqlite.
3 versions of pip/wheel/easy-install is a side effect of the cabbing files. Normally those files are symlinked (hard linked, whatever), but must use cab file as a container due to performance reason and cab file doesn’t support symlinks (or hard links). But you are right: we should make installation more clean, i.e. remove mess.