BubbleGo - check documentation for latest version, it is a Testflight application on ios so not on Appstore.
Plugins are built in html/javascript/css, these are not translatable to react native code, hence 99% of plugins are not compatible. This is a key focus the team will be making upon launch. For now, send the user to a webview with any plugins you need them to use.
Preview mode lacks many features that can only be viewed natively on a device, such as maps, date picker, sheets, push notifications etc. BubbleGo is your Go to for testing
Also most of these answers you could find through a bit of research on the forums. Good luck out there!