Summary: jquery style APIs look rather out-of-place in an ES6 code base. We have already replaced a lot of the calls with ES6 syntax, so the remaining effort now seems reasonable.
Possible issues:
In some cases, I note that certain examples are dependent on some of these functions. As a quick solution, for now we could just have the examples include jQuery from a CDN using an HTML script statement. This will allow us to remove jQuery from our library, package.json and most of our examples, without having to spend too many cycles on how to refactor the examples.
In some cases (e.g. deep copy) there is no ES6 counterpart. In that case suggest we move the function from jQuery mini to a utility file and give it a descriptive name that does not start with '$.'
Finally, I'd prefer to keep dependencies on external lodash modules etc to a minimum, at least for the core library.