[General Questions and Answers] xXx yYy:
1. adb backup is not the most recommended method for backing up Android data anymore. Here's why:

Deprecated: Google has marked adb backup as deprecated, meaning it might be removed in future versions of Android.

Unreliable: It might not back up all data, especially for newer apps that don't allow adb backup.

Limited Functionality: It's complex to use and doesn't offer selective data backup or easy restoration.

2. Extracting data from several Android devices, especially such a comprehensive amount, can be tricky. The methods available depend on a few factors:

Device Functionality:

Functional Devices: If the devices function normally, extracting data is much easier.

Broken Devices: For broken screens or non-functional devices, recovery becomes more complex.

Rooting: Rooting grants deeper access to the device's system, but voids the warranty and carries risks.

Here's a breakdown of how to approach this on functional and non-functional devices, focusing on the apps you mentioned:

Functional Devices:

Built-in Backup & Export:

Most Android phones allow backing up data to Google Drive. Check your phone's settings for backup options. This might include data for Hangouts (messages, chat history), Gmail, and Contacts (linked to text messages).

App-Specific Backup:

Many apps offer built-in export features. Check app settings for options to export messages, chats, or data. This applies to Hangouts, Gmail (might include some Hangouts data), Facebook (messages, posts), and possibly some browsers (history).

File Manager Apps:

Use a file manager app to explore device storage. Some apps, like Facebook Messenger, store data on the device. This may allow access to message history, but won't include everything.

Broken Devices:

Important Note: Recovering data from broken devices is complex and success is not guaranteed. Consider professional data recovery services if the data is critical.

SD Card: If the device has an SD card with accessible data, you can remove it and connect it to another device to access photos, documents, and potentially some app data (depending on the app).

Third-Party Data Recovery Software: These can be risky, so research reputable options. They might recover some data from internal storage, but success varies.

General Tips:

Enable USB Debugging: This allows easier access to the device's file system from a computer (functional devices only).

Target Specific Data: Focus on the most crucial data first (e.g., Hangouts messages, Facebook chats).

Security & Privacy: Ensure you have permission to access this data and handle it responsibly.

App-Specific Considerations:

Hangouts: GAIA IDs might not be directly retrievable. Consider using Google Takeout (https://takeout.google.com/settings/takeout) to download all Google account data, which might include some Hangouts information.

Facebook: Downloading your Facebook data (https://www.facebook.com/help/212802592074644) is the best option for comprehensive chat history, posts, and friend information.

Browser Data: Recovering passwords is usually not possible due to security measures. Browsing history might be retrievable through file manager apps or third-party software (use with caution).

Google Plus: Google Plus was shut down in 2019. Data might be limited, but try Google Takeout.

Remember, this is a complex process. Research each app's specific data extraction methods for a more detailed approach.