I intend to publish my game on the Play store. As an experiment I downloaded and unzipped the file. I don't want to do anything until I know the unzipped file will successfully upload to Google Play Console. Will it work?
I think you're going to need more than just Squiffy to do that.
I'm not sure... but I think you'll need Phonegap or something of that nature to convert your website into an app.
I know for certain it can be done using Inform 7 with an extension called AndroidIF. You'd need Android Studio as well, though, but I have made 2 Inform games into apps that way. It's a little stressful the first go-round, but it's smooth-sailing after that.
The Phonegap method is supposedly easy as well, but, alas... my phone is my WiFi hotspot, so the hosting thing doesn't work on my setup.
Anyway, I'm no help.