Your theory is exactly what I thought since they showed that it was Barney's wedding. I also think thats why they wanted to cast someone as lovable and talented as Neil and thats why a lot of the episodes are about Barney (and more recently) Robin. They could have just had Barney be a really sleazy guy, but they changed him and it was clearly important to the show.
Yeah! I like how they slowly changed him over time and more and more as he got to know Robin. I really don’t have any set theory for the mother, other than the one that it could be Barney’s half sister (which seems a little obvious at this point) but this one, I’m kinda set on.
I also think it would be really funny that the first words Barney said about his wife were, “Oh yeah, you just know she likes it dirty.” (:
