I don't see Emily moving Ricki to Austin. As to her parents not being on the HTD, her parents don't live in NC. I think they live in W. Va. and have a second home in Key West (near the late Ricky's parents.) If the choice was between bringing Brad to meet Ricki or meeting her parents, obviously it was more important for Brad to meet Ricki.
I can't see Emily as Brad's F1. I think she'll make it clear to him in S.A. that she thinks the world of him but isn't quite ready to uproot Ricki or to commit to marriage and moving to Texas, making his choice of Chantal much easier. By having Emily tell Brad, instead of having Brad rejecting her, he won't incur America's wrath.
Ashley still being in school is also a problem. It would mean months apart until she finished, and Brad seems to have a fire under him to commit and start his life as a couple now. I also think she'll have another bout of insecurity in S.A., prompting Brad to say for the umpteenth time that they keep moving backwards. He doesn't want to have to keep reassuring someone who so easily feels "disconnected."
Chantal and he seem comfortable with discussing how they would live in Austin and she seems excited about it, so long as she can bring her pets. He's even ready to look for a bigger place with more closets.
I really can't see it being anyone but Chantal. She's ready now, he's ready now and they laugh and have a lot of fun together.