Hi PowerApps Team,
Please clarify my doubts :
1. Not sure what did you mean. But if you mean how to manage PowerApps in your organization, you could refer to the PowerApps in your organization Q&A.
2. As an admin, you cannot manage apps that created by others. But you can decide who can access PowerApps and restrict users' ability to access organization's business data using Data loss prevention (DLP) policies.
3. About how to Register and use Custom APIs in PowerApps, and Custom connectors in PowerApps.
4. PowerApps UI change won't effect your app UI.
5. There are a lot of limitations and that depends on what you are referring to. For example, PowerApps data row limit for non-delegable queries, etc. About the roadmap, here is the answer from pg:
Keep your eyes open for our upcoming T-shirt design contest!
Fill out a quick form to claim your user group badge now!
Find out where you can attend!
Features releasing from October 2019 through March 2020