Hi,

> i'm not familiar with that approach so can't see what interferes

The most important change is that I can't update it and I can't put
stuff in the system directory nor the user one. 
So I only have access to the project folder, it has to be
self-contained. 

> \definefontfamily [ebgaramond] [serif] [ebgaramond] [features=eb-garamond-normal]

Apologies, my fault, I forgot a part of my email. I don't want the c-t
and s-t ligatures (supposed to be in `hlig`). But I do want the T-h
ligature which is supposed to be in `dlig`. So as far as I understand,
TeXlive comes with an old version of EB Garamond in which all of them
are in `dlig`. Hence my question about self-contained projects with
fonts. 

Best regards,
Andre