Well, roleplay is all about making choices in character, and you did make an interesting choice, haha.

Thundercrash brings up a good point, though. Communication between an Avatar and a Pokemon is a closed, inaudible telepathic connection. Not even a psychic-type Avatar (barring perhaps Uxie) has the power to tell what a Pokemon is saying if it doesn't correspond to her/his type. What Alexis would see is a human and Rhyhorn exchanging glances for a long time, perhaps changing facial expressions at seemingly random times-- which might be enough in itself to make Alexis think Rebeca is strange.