Derive from a base AnimBP class? AnimGraph won't appear

Hi guys, now… i know that if you create a Animation Blueprint class that doesn’t directly derive from AnimInstance you won’t have the AnimGraph.
This causes some problems on our proyect, we have a base class that has some variables and some common behaviour. Our idea was to create a AnimBP Class that could parse or process those common variables and (we hoped) to create common AnimNotifies that had some base behaviour (i.e. Stop attack Anim Notify would set the IsAttacking variable on the Base Character Class to false, etc).

Now that base class would only ever use the event graph (that’s what i intended to do) and the derived classes would create the AnimGraph per character.

Is there a way to implement some base class? or do i have to RE CREATE for each type of character (our game has like 10 playable characters) their animBP?
It feels weird to not being able to encapsulate some common behaviour on a base class.

Also, if this could be done via C++ i have no problem whatsoever (love it).
If this is just imposible to do, what would be your recomendation to treat this “base behaviour” classes?

Cheers guys Thanks!