I think Gabby will be very motivated for worlds after her disappointment in Korea. I think while not a given, maintaining three spots is very doable.
Of course I hope Alaine will continue on and will get back to worlds next year.
It's worth noting that Austman's worlds TES minimums will expire after this season. In addition to Daleman, Osmond, and Chartrand - Pineault has the worlds minimums that will still be valid for 2019. Hopefully Austman will skate better at worlds, make the free skates, and renew her worlds minimums - and improve her season best ranking (she's 8th among Canadians on the list, if I counted correctly).
Fall internationals will give us a better idea of who might get a potential third spot in 2019 (and who is eligible based on TES minimums).
Only Osmond and Daleman will be guaranteed grand prix assignments next year. Chartrand is only 50th on the list so I'm doubtful she'll get a non host pick. I think I say this every year but I hope someone "new" gets the Skate Canada assignment this year.
I'm hoping for a successful return from Kim Decelles, who posted a video on instagram and she seems to be getting her triples back.
https://www.instagram.com/p/BfKFf_bgA1y/?hl=en&taken-by=kdecelles