There would need to be some interaction between the arriving ISV's and Hells Gate in order to restock on consumables for the crew. But given the circumstances, it should pose no problem to the humans and na'vi occupying Hells Gate.
I'd be worried about those in cryo. Jake describes it as an ass kicking, and that's just for a one way trip which would imply even though you don't age as fast, it's still hard on the body. Could a person withstand being in that state for such a long period of time?
But great job on figuring out the scheduling. The logistics of getting to Pandora are quite fascinating