Jean-Luc hasn't competed for the USA for how many years now ? I am guessing they would be better off representing Canada because they wouldn't have to wait a year, just the time it takes for the USFED to release him, which I would think may be shorter because he hasn't been skating competitively for a long time. Do they even have to release a skater who hasn't been active for more than two years ? He is not on their funding list. So ?
If they decided to represent the USA, then Marjo needs a release and they cannot compete internationally at all in 2026-27.
Worlds were later this year, because of the Olympics.
Jean-Luc has been in Montreal since they "retired" in 2023-24 season. He is engaged to Olivia Smart and choreographing. He may have his citizenship process started already. If not, it's most likely not possible for him to get it in time for 2030.
Hannah already has Canadian citizenship. All she will need is a release. The Korean Fed has been very slow with allowing Minsol Kwon to skate for Canada. However, considering that Hannah skated for Canada before, I would think they may be less stingy in this case.
In the end, Zach and Hannah will not be able to compete at all this year, other than domestically for the same reason mentioned above (Worlds being earlier in 2027).
So for logistics, it seems likely that both team will represent Canada.