I don't really think the camera is amazing on OOS or Lineage, use one of the modded Gcams for better photos: https://www.celsoazevedo.com/files/android/google-camera/f/configs-nikita-05/ video is fine on the Lineage camera.
You can pass safteynet fine with the Magisk Hide Props Config module installed, you want to spoof your device fingerprint to an official Android 11 fingerprint, such as the one from the Pixel 4a. You also need to hide Magisk Manager and hide Magisk from the Google Play services and any apps with safteynet checks.
No, you need to flash Magisk and use the above module in addition. Banking apps, Google Pay and games that make excessive use of safetynet such as Pokemon Go all work fine for me.
Not sure in regards to animations, Lineage is fine in my opinion, however i think if its a specific requirement you would have to judge for yourself.
Only the weekly nightly build, start with the latest build and see if you personally have any issues. I'm still on a really old build so should probably update soon, I generally leave everything a few months and update every couple of months as historically Magisk had to be re flashed with every update, I'm not sure if that's still the case however.
How do you spoof your device fingerprint exactly?