Okay, here are a few possible character links:
Baril - as you suggested, I could have met you through my master Bristlebrock Hogensock in Collina. The acquaintance would likely be casual, but I'd probably warm up to your personality faster than I ever did with Bristlebrock's.
Brevin/Tuli - I envision a brief introduction to the two of you while in Collina. Perhaps the two of you had just filched a minor item...a shiny necklace, perhaps? While inspecting your haul, a raven (Trinket) swoops in a makes off with it. You two chase it across the town square and find the bird landing on the shoulder of a bemused dwarf (me) who is only too happy to return the item. Grinder would be perfectly willing to entertain a couple kids with a few prestidigitations before sending you on your way.
Traveling separately, but almost simultaneously, to Alten's Rock, I'd quickly pick up on seeing a couple familiar faces in the crowd of that new city.
Grunlor - I'd likely have met you as one dwarf to another, trying to pick up the news and feel for Alten's Rock over a pint of ale.
Nojin - ?? Pending on background, could be similar to Grunlor. Or, perhaps we both worked guard duty on the barge down to Alten's Rock and found a mutual interest in trying something more adventurous.
Nylarra - possible acquaintance through my master Bristlebrock in Collina (perhaps your family had magical business dealings with him). Otherwise, I'd probably just meet you later through Baril.