I did this transfer in January, using tickets purchased with Avion points. Since it wasn't a through ticket we did have to exit the Inter-Island Terminal, check in at AC and re-clear security. At least they were able to tag the bags through, so we avoided that hassle.

We also looked for an AC or *G lounge, and I think we found it but it was closed. Signage was poor. The deparature lounge for the AC flight was also closed until one hour before the flight, even though it was 90 minutes late and all pax had checked in >2 hours before the revised flight time. When we finally found a GA to talk to she gave a lame excuse about customs regulations. I can't possibly imagine how this affects where waiting pax are allowed to sit.

Good luck.