So from just sending something for Internal Test just now I believe the answer to 1) is no your app is not under review now. This will only happen when you sumbit an app to Production. Your Internal Test app is available now for you to download in the usual way.
As for 2) I think the answer is you can't or you don't, reviews are only conducted when promoted to Production or a new release is added to Production.
When the temporary name will change to the correct one? I don't 100% know that one because I have an app that will always be called something stupid because it will never go into Production (and I have not got to that post review stage), but I believe that once you pass the Production review your app will be renamed to what you intended it to be.
Update 16-Feb-2021: OK so I was incorrect, the name does not stay as the temporary name until you release, you need to submit all the information for release and then wait a bit. In my case I created an app that will never move from Internal Test and completed all the tasks to get it to release and it was still showing the temporary name. Now I look back at the app and it's the correct name, so there's some process that changes it and it's not immediate.