Thanks for the extra info.
I'd previously used Font Book to install the patched version of Meslo from the link you provided, before I posted this thread, just to see if it would work. iTerm sees it, but CoreShell doesn't.
I barely know how to use Font Book since I open it about once a year, so I'm thinking I need to remove the font I installed and use the method you indicated. 
I'm curious why it didn't get picked up from Font Book, though. I assume I did something wrong; I'm just not sure what.
EDIT: The shell script worked perfectly. 
Though, if I'm honest, I'm now more than a little distracted by the realization that Font Book doesn't work the way I thought it did--or possibly at all. ¯_(ツ)_/¯