Bimlas,
I tried to follow the discussion, It seems you are asking to have a tag pill that on clicking does not list the tag but lists tagging/references list (from tiddler info).
To me that at first was asking something to do something its not made for. However a few thoughts came to me
The Following can be used to generate a list of tag pills from any filter {{{ [tag[TableOfContents]] ||$:/core/ui/TagTemplate }}}
So you could use the same filter to find references "[all[current]backlinks[]sort[title]]"
{{{ [all[current]backlinks[]sort[title]] ||$:/core/ui/TagTemplate}}}
Or Tagging
{{{ [all[current]tagging[]] ||$:/core/ui/TagTemplate}}}
This produces a list of tag pills that satisfy the filter(s), You could wrap the above in a popup to get close to what I think is your requirement. I am as yet not confident building popups but you seem to be.
Now on playing with you macros I see what you wanted better now.
I tried replacing your link in the references macro with {{||$:/core/ui/TagTemplate}} to provide a tag pill for each item in the popup, but I think we need some more popup settings, another state tiddler? to make this work.
A more generic solution?
I played with your above macros and they are quite useful, they do something similar to what I did in the past, I created a custom tag macro, that allowed me to have a tag pill called Tagging that on click opened the tag pill drop down for the current tiddler. The advantage being you only ever saw a tag pill called "tagging" if the current tiddler was used as a tag elsewhere, and you did not end up with a tag pill that was the same as the current tiddlers title. We can do this with you macros.
What I am thinking is we could modify your above macro(s) to have a default name of tagging, and a default filter that finds tagging tiddlers, then have the drop down list such tiddlers but with their own tag pill (so you can see what they tag). We could then permit the passing of an alternate name and filter so as to be able to use the same macro to show references or any other useful "filtered" relationship, in a drop-down with a list of tag pills.
An advantage of the current tag pill drop down is it also lists the actual tiddler, so you can open it as well as the items it lists. Also if you install Andrews Open All Plugin from
http://t5a.tiddlyspot.com/#Andrew%20Harrison (in library) you can open all tiddlers that are listed in the tag pill dropdown with one click.
Just some thoughts for you, that may allow you to simplify/generalise your macros. Being able to open all tagging/references in a click, or open the named tiddlers would also be helpful,
Tony