Hi, I wrote a plugin example for Tapjoy, Firebase and AdMob.
(Oops, The forum says I can't post a link...)
It's not well packaged, in other words it doesn't support one click integration.
To integrate it into your project, you need to touch some native code.
There is Ads plugin but Tapjoy or Firebase support analytics which is not covered by Ads plugin.
That's one of the reason I wrote this.
Please leave a feedback if you have questions or suggestions.