Is it possible and if yes where can I find and see that data?
My other question is, if my package version is successfully created, would it show up here in this list of packages?
No. Only installed packages appear here.
Right now, I don't think there's a timeline for when, or if, Second-Generation Metadata will appear in Setup. It's not "meant&...
As at Spring '21, 2GP managed packages do not support component deletion, as covered in the 1GP vs 2GP gap documentation. A rename is equivalent to delete (old name) and add (new name). Salesforce plan to add this ability in the future according to webinars and presentations around 2GP.
Your solution, therefore, is to add back in the ExampleCtrl class to ...
The solution, provided by the Salesforce support, was to create an org shape:
An org shape creates a scratch org that mimics your Dev Hub edition. After creating an org shape, removing "edition" from the project definition file and its features, ...
I was not aware of the inability to remove flows (1GP beta), so thanks for sharing. However, I believe you are misunderstanding what this means. I believe this is simply saying that flows from 1GP or 2GP managed packages are not subscriber deleteable, rather than set in stone within the package itself when using betas.
In terms of other beta "gotchas&...
No, you're not missing anything. Each package may only be one directory. From your question, it appears you want two packages, with the force-app package depending on the common package.
No, there's no automated way to load the data. You could use something like sfdx force:data:bulk:upsert or sfdx force:apex:execute to automate importing data, but this needs to be a separate step. Unlocked Packages are not meant to be used in a subscriber/ISV model, so there's no provision for a post-install script.