You need to have had Monica meet the red headed prostitute before the ep4v2 scene with the gloryhole will open. To meet her Monica has to work at least once for Mommy on the street. And as of now the v5 scenes in the Shiny Hole will not show up in the event list unless the gloryhole scene has been played.
This is a quote from the walkthrough you linked.
"v 0.2
You must be registered to see the links
needs
to head to
You must be registered to see the links
in the evening, select the
"Toilet Cleaning" option from the menu, and clean the bar's toilets instead of
You must be registered to see the links
. The scene is available provided that Monica is acquainted with the prostitutes working for
You must be registered to see the links
at the
You must be registered to see the links
, and that
You must be registered to see the links
isn't at the bar that evening (
animated scene)."
It's also needed to have played through the VIP scenes in ep4 up to when Tiffany is working there for the v5 Shiny Hole scenes to be available, not to just have the VIP path open at the start of ep4.
It is weird now that to continue any Shiny Hole content in ep4 Monica needs to be working both of the prostitution jobs. As you said she was able to become the manager at the end of ep3 without having to have anything to do with prostitution.