XFCE installation about cinnamox-gtk-theme HOT 1 OPEN

I've only had a bit of experience using Cinnamon themes and / or Cinnamon + Xfce themes (or whatever).
Just to make sure you know, there are lots of themes written specifically for Xfce4, which may be easier?

How well any theme written for one desktop environ. (DE), but installed in another, is trial & error.
Could well depend on the theme, but as Smurphos said in the post you linked on linux mint forums, " Be sure to read the readme...". It tells how to install. Just unzip to your ~/home /.themes directory. I advise keeping the orig theme. zip file. If editing a theme file goes way South (it happens), can quickly replace the few files you've edited.

Replacing edited files would wipe out all / any (good) edits you've done, so make a BU of edited file(s) you're about to replace. Label them w/ meaningful names . So you don't have to hunt so much to find the lines w/ exact changes & colors, that you still want.

If you ever reinstall a theme, or slightly later version, you can compare old, "customized" files (or directories) - like gtk.css, to new one, using an app like "Meld". It's in Mint's repo. It clearly shows where every difference is, down to one extra empty white space or comma, etc. Very handy for quickly finding a line # where you customized a font-size or color & want to add it to the new (or clean) file. Trust me, once you learn to use it, it's useful.

That, and a good text editor. Several people mention Geany, which I've used for 4 yrs. It's search function is GREAT.
I have to say for me (obviously lots other pro-coders & amateurs), getting a different, dark, color scheme makes it FAR easier - just by not looking at light background, The brighter colored schemes on dark BG makes it much easier to find errors, and see spacing errors. Geany includes a few themes & Geany's site has many "schemes" to choose from & you can edit, if a color doesn't suit you.

I use a modified version of "Black" color scheme.
One edit was make white space "dots" more visible. Made whitespace bold, deep yellow on black BG.
white_space=#FFFF00;;true; white_space=white_space,bold

from cinnamox-gtk-theme.