I just realized that in Warriors Power of Three, after Jayfeather, Lionblaze, and Hollyleaf found out that Squirrelflight was not their biological mother, it honestly should’ve been kind of obvious it was Leafpool.
Because at that point, Jayfeather and Lionblaze were confirmed to have powers, meaning they did pertain to the prophecy of being Firestars kin of kin.
There were only three cats that were kin to Firestar then XD. Squirrelflight, Leafpool, and Cloudtail. Squirrelflights confirmed not to be the mother, and why would Cloudtail have a reason to lie?
Sooooo how tf did it take Sol telling them that they figure out it was Leafpool?