So far: I recently got distinct highlighting on the namespace and name parts of keywords and symbols. I'm now trying to get distinct highlighting for typehints and metadata sugar like this ^:added-metadata

Metadata syntax highlighting is working great now. I can pretty easily apply type face to typehints, property face to metadata. I've added preprocessor face to reader tags, comment-delimiter face to the discard tag, warning face to deref symbol. Quote syntax ``~@` and var quotes #' have a delimiter face.

do you know how this might interact with lap's highlighting?

Do you mean lsp's highlighting? I can't imagine it will be different from how it works today, since I think lsp applies highlighting after the major mode does. I haven't done much testing, but with eglot and clojure-lsp it still does things like highlight matching symbols when the cursor is over it.

right, that's my understanding, it enhances the major mode's highlighting, but I was curious if tree-sitter changes that at all

I've also wondered as a pie-in-the-sky thing if tree-sitter couldn't be integrated into clojure-lsp but that's not super relevant here

Well I can say for sure that eglot with clojure-lsp work well with my tree-sitter branch. I can imagine lsp-mode will as well, but I don't use that library personally. I'm not sure what clojure-lsp would gain by using tree-sitter. I believe it already uses rewrite-clj to fill a similar role as what tree-sitter would do. Maybe it would be faster to parse, but I'm not sure what else it brings to the table. The lsp maintainers might be interested though