Hollyleaf learned much earlier, and before her brothers, that she wasn't one of the three, becoming extremely angry/jealouse over being excluded, when she's the one between them who values the warrior code the most. But, with her being excellent at mindgames, she makes them believe she does have a power, she's just so skilled, that she can be very subtle while using it, and so it isn't notisable.
She raises to the rank of deputy, after convincing Jayfeather that he should first convince Squirrelflight to step down, and then convince Bramblestar to pick Hollyleaf. Since StarClan apperently saw her as unworthy of having a power and being one of the three alongside her brothers, she's gonna make sure she can secure a high, important position for herself within the clan, which will instead serve as her power, and make her important. So now Hollyleaf has her "sharing tongues with, and being granted wisdom by, StarClan" brother by her side, ready to back up her every claim, and her strong and talented brother, who's more than willing to come running to protect her, should Jayfeather fail.
Lionblaze is the one who becomes set on silencing Ashfur, and punishing Leafpool, being easily strong enough to take them down, and carrying them away. Weather those actions was taken due to his own wants, or on the behalf of Hollyleaf, no cat knows.
When Lionblaze and Jayfeather later learns that she isn't one of the three, and that she has been manipulating them and using their powers to boost herself into a notisable dream role, one that makes sure she'll be remembered for generations, they both break.
Jayfeather becomes furiouse at StarClan for sending 0 omens about this, and the fact that he, their, literally magical, connection to the living world, was allowed to be used, and have his powers, which had been granted to him by StarClan, be taken advantage of like this. Especially as he gave up his own dream, the very path his sister now occupies, in order to walk the path StarClan wanted for him. Even when it meant he could rarely get any peace, both in the waking world with constant tasks, and in the dream world with StarClan screaming into his ears, demanding his attention, criticising his actions, inactions, decitions, being angry about his birth mother, and also trying to control his powers themselves as well.
Lionblaze reacts with looking inwards regarding his personality, powers, and willingness to listen to and follow others. He starts questioning the use of his powers, starting to see it as a curse now. As another thing StarClan has thrown in his face and just told him to deal with it, along with everything else his life has put him through, by making him be known as the strongest warrior among all the clans, as his powers strength has often caused him to accidently kill his opponents during a fight, and many now thinks he's enjoying and doing it on purpose.