Glyphs won't export font family properly

I hope I’m not too much of an interloper. I’m a total newcomer to typeface design, forgive me if I misuse terminology. I’ve taught myself everything up to this point, but for this final problem I need help.

When I export my font—which is not so much a font but just 16 characters in Light, Regular, and Bold—only the light weight is available when I open it in Font Book or Pages, and oddly it’s labled as regular. I just need to successfully export a font family with all three weights.

While I’m asking for help I might as well put forward other questions, since even what I’m trying to fix is an awkward workaround to my original goal. All my troubles are to create a mere 16 characters for a constructed language ( ) whose alphabet otherwise exists among available characters. I’m doing it in the style of Helvetica so it can be used with the rest of the font.

Obviously it’s inconvenient to splice fonts together (original Helvetica and my font) but it’s vastly preferable to not being able to type them at all, instead using wrong characters as stand-ins. Originally I wanted to just duplicate Helvetica and fill in the 16 characters I needed to replace. Manually reconstructing the entire font glyph by glyph is possible but far more effort than I’m willing to put in.

I’m wondering if there’s a way to import a duplicate of Helvetica and swap the characters? Also if anyone can give me some sort of guidance (link to a website perhaps) about proper kerning / spacing, that would help quite a lot too. I appreciate any help greatly, thanks in advance!

Sounds like a font cache problem. Do not use FontBook for testing a font, rather the Adobe Fonts folder:

The only other reason could be that the masters are not compatible and the interpolation values diverge from the master values. There are multiple master tutorials in the Tutorials section. I especially recommend this one in your case:

Not a technical problem:

… but rather a legal one. You would not be allowed to pass on your modified Helvetica. I recommend forking an Open Source font for that. There are plenty on GitHub, e.g. Source Sans.