I am not extremely familiar with the Svefra, but I'll do my best to help you out.
Based on what I glean from the Svefra lore page, my guess is this:
It would take some form of extreme circumstance for a Svefra to leave the Sea (though it's not impossible). Would she be leaving voluntarily, or did something happen that caused the matriarch to cast her out?
If she did go inland, there are Isur who travel outside of Sultros, and it's conceivable they could have met up somewhere (Though, how far "inland" is inland? Seems to me there are plenty of port towns that might serve your purposes).
As for taking the two-year-old, given that Svefra children are raised communally, she probably would have had to steal it from them, so I imagine they would be peeved. They would probably welcome the child back with open arms, however (as long as the child's eyes are blue, of course. Children with non-blue eyes are thrown overboard though, so it probably wouldn't have survived for two years if that were the case).
If you have any further questions or would like to discuss your backstory, please feel free to PM me