I didn’t see it anywhere from quick search but I am assuming that a counterattack is NOT a buff. Can anyone confirm that with certainty?
Riposte definitely IS a buff. I cannot quickly find where this was asked and answered, but if you feel the need for a source, I’d suggest finding out when the last buff booster tournament was, finding that thread, then sifting through the whole thing.
Also, N.B. it is listed as a buff in the status effects thread, and it is even specifically mentioned that it counts as a buff in this type of raid tournament.
The Hatter can steal it, so I think it’s a buff.
Perfect Riposte is a dispellable buff, yes. Essentially any beneficial status effect applied to your heroes will qualify as a buff.
What’s worth noticing, shared damage is also considered a buff although it could be either beneficial or disadvantageous, depending on circumstances.