Welcome to FT and the Delta forum! This is indeed mostly a casual blow-off-steam thread, but
1. I doubt it; even if the point of SEA is to be *a* gateway to Asia, it's probably not going to be *the* gateway to Asia, and although I am not an expert by any means on aircraft capabilities and route planning I suspect using the A350 from SEA would be a waste of its range.
2. No idea, but might've gotten discontinued for winter? The non-stop seems to come back in March on the schedule at least.
General 350 thread:
2017 The Year of the A350
This is probably the most recently active but ominously named CVG-related thread
RIP CVG