I was almost sure that nothing would be better than upgrade girls which upgrade your gains so with it you would be able to upgrade other girls faster blablabla... But then I finally decided to make a test and upgrade just bunny at the office. Contrary to my expectations that I would stop at some lower level to accumulate money, bunny just went straight to the minimal reset stage(3006) just like if Stelle didn't need to exist at all. Now I really am in doubt and would like to see what you people think.
I also think this questioning can be applied to Clara
One thing that I need to add is that I since I was focusing all my atention to upgrade Angela I don't have Estelle' s multiplier perks(yet), so it's just her original state. And these are my reward crafts