How many of the Season 1-2 end scenes with A were MonA?

hard to say without an extensive rewatch and even then the writers still might pull some stuff in the final ten episodes to try and tie the new -A into whatever was going on back then. realistically most of them if not all of them were intended to be -A. though mona herself wasny decided on until season 2.

*when life gives you lemons*
Sara: are you a sour lemon?

I'd guess that 95% of them were Mona. I can think of one that wasn't, which is Alison's memorial getting smashed at the end of the episode, since we later find out Lucas did that. But probably no way to know for sure.

The world isn't split into good people and Death Eaters.

I think most of them was mona and some might have been lucas since mona revealed lucas helped her from time 2 time