The complete composite feature have to support all latin characters.
All Latin is not specific enough, as there is no consensus about the full character set. See:
https://typedrawers.com/discussion/4873/full-character-set-of-latin-script
We will consider supporting more characters, so please let us know exactly which ones you would like us to include.
That is not true. All latin characters there are in unicode charsets.
The majority of those additional characters are not composites, but simple glyphs.
You really need to give something specific for Erwin to work on.