to go find Luke. If she wasn't in the Skywalker/Solo family I don't think it makes sense. If Leia had just met Rey and they had no connection, I'm not sure why she would be sent to get Luke. It wouldn't have just been about her getting trained - their whole goal throughout the film was to find Luke to get him to come help the Resistance, from before they even met Rey on Jakku.

It's possible that Rey is a random, but with all the hints they dropped it would be a bit disappointing that they kept it a big secret throughout this movie and the couple years before the next one to reveal nothing.