Will Zenfone 8 be updated with Android 12 ???
Of course. Beta has been available for a couple of months.
Is this beta only for ZENFONE 8 or is it for ZENFONE 8 Flip?
No idea. Mentioned webpage says nothing about Flip though.
The aosp beta looks like it's only avaliable on the zenfone 8 but the final zen ui based beta should be available on both at the same time
The linked beta program is for Zenfone 8.
From the updates section of the smartphone Asus proposes on Zenfone 8 the subscription to the beta program for Android 12 .... Considering the bugs that a new system could have, I will not install beta Android 12 !!!! I already have too many problems with the smartphone let alone if I start being a guinea pig for Android
Then we suggest you to not enroll in the Android 12 beta program.
Does the Android 12 beta update wipe all user data ?
Yes. It wipes all user data.
Depends which beta I think. If you install the current beta offered on the website then yes.
If you are talking about the upcoming official Asus android 12 closed beta for which you have to register for, then I don't think so. It is supposed to reflect how all other users will get it, so it should be an OTA update