While I don’t have a vested interest in this thread, I will interject another comment anyway.
Yes, of course.
Except, of course, that unless one physically relocates, one does not exactly choose his/her parish. The law says it’s all by geography and, often times, not logical or proximate geography either. This applies to the Latin Church (where it does happen that a person may reside 100 feet from a church but is canonically ascribed to a different parish miles away), as much as it does to the Eastern/Oriental Churches, albeit that they’re far more spread-out. So, no, one really cannot pick to which parish one is ascribed.
Anyway, looking at the
Syro-Malabar eparchial website, I count 16 Knanaya parishes & missions in the US. From what I see there (and perhaps I’m mistaken), it appears that wherever there is a Knanaya parish or mission there is also a “regular” Syro-Malabar parish or mission (it may not be “next door” but still in the same general area). That leads me to think that what they have is a jurisdictional overlap, and it would seem that this was done on purpose in order to address the sensibilities of the Knanaya faithful.
It does not seem to be that, where a Knanaya marries a non-Knanaya, the person is expelled from the Church. Yes, it may be that the person would no longer be ascribed to his/her particular Knanaya parish/mission (they would, rather be ascribed to neighboring “regular” Syro-Malabar parish/mission, but that is very different from being denied membership in the Church. And the person could, of course, still attend and participate in the life of the Knanaya parish/mission, although their canonical records would be held at the “regular” Syro-Malabar parish/mission.
Maybe it’s just me, but frankly, I really don’t see a problem with that.