Can I have multiple apps in AppStore and PlayStore use single Facebook App? For example I own a brand and launch 3 or 4 or 5 apps under the same app on the both platforms. I want to have shared friends list between them and maybe some other things.
Yes. You can. See here
You can use one Facebook app ID in multiple Android apps. Just use the same app ID in another app for login, sharing, and so on.
For deep linking and opening your app through notifications and other means, we only support a single package name/class name combination.