Shakky is most likely in Seastone Cuffs, here, I don't think she can use Haki.
I think Rayleigh didn't use Haki, because he didn't want to hurt Shakky.
If he had used one of his strongest attacks, she could have taken damage/he could have destroyed the room and hurt her.
Instead, Rayleigh focused on the woman in front of him he loved, rather than powerscaling.
But we don't know anything about that kind of thing here
She told me she was an Ostrich, but she was really an Emu, and I've never recovered.