It's doubtful Mathis and John would know her, what with Mathis being all ~private~ (though I do hear Cat and Corin have been SCHEMING! So this might change...) and John being all anti-evo.
BUT! Cat could know Toby, or at least Toby would know her. Through Corin perhaps? Since Rin and Tobes are buddies. Toby will also be attending plenty of PEM events!