An alternative is optional static languages like Groovy or alternatives like python Type Hints (https://www.python.org/dev/peps/pep-0484/) are better than pure dynamic languages.
There's also the commercial aspects of static typing in a dynamic language. After 10 years, Groovy introduced the annotations to optionally statically compile code in order to compete with Java instead of complementing Java, which changed the business purpose of the language and their relationship with Oracle.
I see the project going one of two ways. One all loosy goosy. One all statically typed. At which point what did optional typing add? Pick a side and go for it.