I could see Wenatchee maybe working for the WHL in the distant future. The arena is nice and new, and its intimacy reminds me of the Kootenay RecPlex. Travel would be doable: Wenatchee is relatively close tot the other US division teams, and some of the BC teams (Kamloops, PG, Kelowna etc) drive through the Okanogan to get to and from Tri-City/Spokane anyways. It would be a smaller market for the league (32,000 in city, ~50,000 in surrounding area), so it's probably best to let the BCHL operate there and build fan support assuming they can get their lease issues worked out.
Wenatchee makes no sense for AHL. Teams would fly into Seattle and have to go over Stevens Pass, which is no picnic in the winter to say the least. The nearest airports (Yakima, Moses Lake) have limited commercial service, and are at least an hour away; plus, to cut costs the AHL teams don't typically utilize small airports. The typical Abbotsford trip for an AHL team is an all-day flight to Vancouver or Seattle followed by a bus ride of 1 or 2 hours to Abby. Wenatchee would be worse.
KeyArena could make sense as a temporary landing spot for the Canucks for next season while they try to either crack into Abbotsford or set up Rogers Arena for 14-15. Many good reasons have already been mentioned (proximity to Vancouver, market size and interest). The KeyArena blocked out dates for the return of the Sonics that isn't happening now; while those exact dates may not still be reserved or available, the AHL Canucks could easily negotiate their way into the Key since, well, not much happens there during the winter. The primary tenant during hockey season is Seattle University basketball, which routinely draws crowds under 1,000. It's also not an ideal concert venue, evidenced by many high-profile concerts instead going to the Tacoma Dome. The calendar is wide open for hockey.
If I had to bet, especially after reading wildcat's convo with the Canuck, I'd see them settling somewhere back east, in one of the several cities brought up in this thread (Trenton, Lowell, ...)