Displaying some characters with all-icon instead of my current font

Usually people want to print some characters and end up having strange squares clearly telling them this character is unknown by their default font and they have no fallback font for it.

My problem is quite the opposite, my current font (Fira Code) actually knows all the characters and seems to not agree with all-icons on some of them.

In my custom.el file I have a function to display some bullets as special characters and I explicitly wrote:

I put screenshots because it looks like StackExchange can’t handle these unicode characters:

'(? ? ? ?) 

When I put my cursor on one of these characters and M–x describe-char I get the following answer:

Note that the code for this character is #xe3d0 (and the other three are #xe3d(1/2/4)" so I could write my list like this:

'(#xe3d0 #xe3d1 #xe3d2 #xe3d4)

Anyway, when I restart my emacs to have my prettified bullets:

And even better, if I go back to my customisation file (at least it’s coherent):

I tried adding:

(set-fontset-font "fontset-default"
                  '(#xe3d0 . #xe3d4) (font-spec :name "FontAwesome"))

But it didn’t change anything.

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[EDIT] If I write this list (according to https://en.wikipedia.org/wiki/Enclosed_Alphanumerics):

'(#x2460 #x2461 #x2462 #x2463)

I have the wanted result:

(set-fontset-font t '(#xe3d0 . #xe3d4) "Material Icons")