Rafe spent a lot of time at the orphanage, not necessarily being an orphan living there. He indicated that the nuns put him on the right path. I guess it’s possible that the mother ‘gave him’ to the nuns to raise when she couldn’t control him. No mention of the father so I wonder if that means a bunch of different ‘fathers’ or as I tend to refer to them when they are around for the deed only: sperm donors.
I also wondered what mother would send her daughter to go find her brother/sister when she was leaving town to go visit her mother on a holiday no less?! That story sounded so contrived! What is really strange is that neither Rafe nor Arianna seemed to think it was strange that their mother did that with their sister. Maybe she isn’t a very responsible mother? More likely just a way for the writers to add a new character to the screen.
I think you’re right in the hooking up with Will or Chad.