Proposing a slight edit. Bolded portions are my additions:
"It may include a maximum of 2 Pokemon/forms, which should share at least 1 of the exact same typing combinations, set of abilities, statlines, and full movepools, with the remaining stages having at least 2 heavy similarities (eg at least one shared typing, at least one shared ability, etc). If the Pokemon/forms share 2 or more stages completely, there is no requirement for the non-shared stages to be similar."
If they share 2 or more stages completely, I don't see the need for the additional requirement of heavy similarities.
Also going to throw out the opinion that, as a person who tends to take thing literally, it might be good to insert a clause about subjectivity somewhere, so that if someone has a framework that doesn't quite fit the rules but could be argued, they know that that door is open in the first place.