I think the canal rumor was a result of the more hashed out DVC at CBR rumor. Folks rightly guessed there had to be some sort of premium access to a park, and the close proximity to Epcot let folks armchair imagineer the solution. I know I was one that spitballed a canal might be an option.
Some thought another entrance at Germany would work, and maybe a water way there, and others thought a water way west connecting into the DHS-Epcot canal.
I'm still surprised at the routing of the skyliner. Makes perfect sense as the focal point on Riviera, but feels like like the skyliner route is an after thought or add on from a pre-existing plan.
I would have used the Riviera as a hub, so it had a non transfer option to each park. The turn station is not ideal.
I might have torn down Aruba for the Riviera and put the hub on Jamaica.
In general I think the Aruba location would have been more ideal overall for the riviera for views, transportation and the like, but there must have been some other overriding factor.
Depending on how the sales work out for Riviera, I could see them trying to do something similar on the south end of POR french quarter/ north end of OKW complete with skyliner connecting Disney springs(and their resorts) with the front gate of epcot.