Hey there!
1. As the metagame develops, the council looks at things that might be unhealthy or broken for the state of the tier. We will generally note this in a Council Minutes post. If the issues don’t seem to have answers developed for them in time, then we will plan for a suspect test.
2. If a Pokemon has a suitable niche within the tier, then it will be ranked. Generally, an explanation of decent depth on the role of the Pokemon alongside mandatory replays will put it on the VR slate, where it will get voted on by the council. A Pokemon whose niche is tied to one playstyle ties it to that playstyle’s vability. For example, if a Pokemon is to be ranked for its prowess on Trick Room (say Glastrier or Stakataka), then one would have to prove that TR is a viable playstyle in the tier. This applies to most pure offense or defense structures, and its why you see things like Moltres ranked.