You could start looking for Leonardo Ideas from potentially impactful ideas that felt like they were in the adjacent possible in the past and precisely identify what constraints prevented them from existing.
This takes advantage of criteria #1 from the fact that Leonardo Ideas can be systematically identified (Would be impactful if existed.) and is depending on past excitement both as an indicator of impact and that the idea might be in the adjacent possible. People get excited about things that feel possible.
Practically, this could involves