Any Perl users here?

[Gribouillis]

Will Python3.5 and 3.6 scripts (and modules)run under 3.7.

Yes they will. New python versions usually don't break old code, the most notable exception being python 3 which broke python 2 code.

Until you feel the need for it, you can very well work without pyenv. I do it most of the time.

I can't tell you about the /Wheel and /HTTP directories. Why not try to remove them?