Thunar File Manager and the Custom Icon dilemma

I am running Zorin 12.4 Core and I have settled on Thunar as my default file manager for many almost (Or nearly?) irreplaceable reasons. But I have one grating, annoying issue with it. It has a lot of trouble displaying my default Icon Theme. All other file managers (With the excpetion of one which doesn't by design) have no problems with it.
I have searched and searched and searched some more... following instructions about the inode directory and so on. All to no avail.
I had given up - with great sadness and tears in my eyes- and for months, coped with it. But... recently, I installed Zorin 12.4 Lite on another machine and IT shows all the custom icons in Thunar properly.
What gives?
I am at a complete loss.
Probably because 47 of my 54 brain cells are overheating.

You answered it in your thread - Core is Gnome, Lite is Xfce (although it no longer uses Xforms:

"Olivier Fourdan started the project in 1996 as a Linux version of the Common Desktop Environment (CDE),[7][8] a Unix desktop environment that was initially proprietary and later released as free software.[9] However, over time, Xfce diverged from CDE and now stands on its own. The name "XFCE" was originally an acronym for "XForms Common Environment", but since that time it has been rewritten twice and no longer uses the XForms toolkit. The name survived, but it is no longer capitalized as "XFCE", but rather as "Xfce". The developers' current stance is that the initialism no longer stands for anything specific. After noting this, the FAQ on the Xfce Wiki comments "(suggestion: X Freakin' Cool Environment)".[10] The Slackware Linux distribution has nicknamed Xfce the "Cholesterol Free Desktop Environment", a loose interpretation of the initialism."

Source: https://en.wikipedia.org/wiki/Xfce

One thing I tried was that I downloaded and installed the Xfce desktop onto my Zorin Core machine. I had the same result as initially on the Gnome Core. But on the 12.4 Lite, that issue is not present.

(I have since removed Xfce desktop from my 12.4 core machine). Downloading it via terminal is a very different experience from getting it packaged from Zorin, where the Zorin team took much more into account- it works better on Zorin Lite than on a terminal install...)