Non-detecting some downloaded fonts on EndeavourOS

Hi, and thanks for any thoughts.
I’m running EndeavourOS, a fork of Arch Linux.
I just downloaded and installed a number of fonts from FontSquirrel.
Most of them are detected in XFTerm’s builtin font selector, and rendering beautifully. But several aren’t, although the Arch Linux CLI font config tools are certainly showing all of them. Just wondering if anyone has any experience with this, what the root of the issue might be – XFTerm, . . . the fonts themselves, . . .? and if anyone knows how to fix?
The fonts not appearing in the XFTerm font selector are:
all Lato .ttf fonts
all Montserrat .otf fonts
all Alegreya .otf fonts