Were Python 3.5 and 3.4 installed into the same location? That would explain some of the problems. It looks like it's finding it from the 3.4 key and then skipping the 3.5 key because the path is the same - hence "py -3.5" doesn't find it.

Also, we apparently are lacking some Unicode support in the launcher :)

If you delete all of the PythonCore keys and run repair installs for the versions of Python you want, that will restore the ones you need. Our installer deliberately does not remove anything in site-packages (except for pip, and only if it were installed by our installer).