Dual Messenger - Where are files stored (e.g., WhatsApp)

Question

I had a working WhatsApp (say, WhatsApp W1 in phone PC) in my Samsung J7 Prime, Android 7, recovered with the usual Backup to/Restore from Google Drive, from phone A (PA).

I meant to install a Dual Messenger^* - WhatsApp, restoring for it a copy (W2) from another phone (PB). So I would have

W1 PA -> W1 PC
W2 PB -> W2 PC

This is the only reference I found on how to do it (which is a workaround, as if no "official" way of doing it existed). Since some people acknowledged in comments that it worked, I followed it. I skipped the part of recovering Media from W2 PB.

Now I have the two working WhatsApp accounts, that is fine, so far. But I am left with the following file structure:

/storage/emulated/0/WhatsApp/.Shared            <- From W1 PC
/storage/emulated/0/WhatsApp/.trash             <- From W1 PC
/storage/emulated/0/WhatsApp/Backups            <- From W1 PC
/storage/emulated/0/WhatsApp/Databases          <- Copied from W2 PB
/storage/emulated/0/WhatsApp/Databases_PhoneA   <- Renamed from W1 PC
/storage/emulated/0/WhatsApp/Media              <- From W1 PC

I have questions:

1. Where are files (messages, media, backups, etc.) for each WA installation stored?

2. Will I end up with a "broken" WA structure, which will cause problems? (so far everything is working fine).

3. Is /storage/emulated/0/WhatsApp/Databases_PhoneA needed?

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^* Dual Messenger is a feature of Android 7 and up that allows natively two accounts of the same Social Network on the same device, which can even be open at the same time. Before, one needed an application like Parallel Space to accomplish this.