let me answer your questions one after the other:
1.) If you succeed the revenue limit with your V-Play apps and games, you would then need to upgrade to the next higher license. Let me put it this way: the rev limit helps small and indie developers to get a low-cost tool for creating games rapidly. If their games are not successful in terms of revenue, the cost for V-Play will also stay low and so there is no risk in using it.
If, however, the games are successful or it’s a successful company using V-Play, you will probably have higher support requirements, want to add more “higher-tier features” which match the higher-tier licenses.
2. & 3.) Starter plan does not support monetization plugins (see our Pricing page which plugins are supported in Starter license) – so if you would like to make money with ads or in-app purchases, I would recommend the Indie license.