When Lily and Marshall are thinking of girls to set Ted up with, Marshall suggests Natalie but in 1.04 (Return of the shirt) at the end the narrator says that Natalie was married within 1 year and has a kid, so at this time (5 years later) Natalie is married and has a kid.
(at around 20 mins) When Ted finds Barney's phone and answers it, a person appears to walk past the window of the apartment. However, it is actually a reflection of Robin continuing to clean (you can see the yellow gloves she is wearing to do so).
Ranjit is a driver who is originally from Bangladesh and so must Bengali, but the actor is an Iranian who speaks Persian in the scene where they are comparing a duck to a rabbit in the bar.