Perhaps a more flexible system would be to use composition and declare a JuceInterface interface with all the necessary method names. Then implement that in a Juce class which becomes a member of the generated JuceActivity.
This way we could inherit from whatever Activity class we need and also use the generated Juce bridging code, without risking breaking things when we update Juce.
I’d be happy to send a PR when I get the time if this issue isn’t high on Team Juce’s backlog…