Possible to edit Firebase Cloud Functions on an iPad and deploy changes?

To fix this issue I dont know if this is what you're looking for but you can either
firebase deploy --only hosting or database or functions or install firebase in different

Hope that helps Firebase CLI tools 3.8.0 has added the ability to deploy specific functions.
firebase deploy --only functions:func1,functions:func2

--only <targets>     
only deploy to specified, comma-separated targets (e.g. "hosting,storage"). For functions, 
can specify filters with colons to scope function deploys to only those functions (e.g. "--only functions:func1,functions:func2"). 
When filtering based on export groups (the exported module object keys), use dots to specify group names 
(e.g. "--only functions:group1.subgroup1,functions:group2)"

wish helps you What worked was to make a fresh directory and set up the "Hello world" tutorial from the Firebase documentation. This creates a node_modules directory that includes firebase-admin. I then swapped the new node_modules directory with the old directory and it worked.
The problem appears to have been that I had firebase-admin installed globally so npm install wouldn't install it locally in my functions directory, but firebase deploy can't find global Node modules, it has to have local Node modules. That's my guess.

fixed the issue. Will look into that further TypeScript has a transpile phase that's required to get the code into JavaScript (ES6), which can be understood by Cloud Functions. You will have to make that transpile phase happen in order for the emulator to pick up the changes.
Using the package.json that's created by the Firebase CLI for new TypeScript projects, you can run npm run build to transpile without deploying. Or you can use tsc --watch to have a process automatically transpile changes to your TypeScript.

With these it helps Everything from your functions folder gets deployed, except node_modules. It doesn't matter what your index.js contains.
Cloud Functions will reconstitute your node_modules folder on the backend by running npm install. So, the contents of your package.json matters a lot.