Good points all around!
The nobles (Pyrrha, Tinwë, and Fah'lin) probably knew each other pretty well growing up (personally I'd go with friends), and they each have developed an interesting insight into magic. It seems like the three of them would likely be ready to team up. And maybe Pyrrha knows Aetoris and Oma, so that would be a good link. Beyond that, Tinwë probably has heard stories of Aetoris' exploits in the elf military.