In thinking further, they only make you claim bags, go through customs and re-check them when the connection is for another destination within Canada, so bags should be checked through and there ought not to be that element to the connection.
I am a bit baffled as well by the time estimates, since at YVR domestics are in one wing of the main terminal that might be a 10 minute walk at most, and then flights to/from the US are in one part of the other wing, and the international ones go in another part, meaning walking time is only about 5 minutes. It might be a matter of getting out into the main terminal and then getting back in and going through security again if the gates are not in the same part of the airport.
I took a look at the airport's web site and this is their link: http://wwwnew.yvr.com/en/navigating-...rough-YVR.aspx -- it doesn't offer help on timelines, but there is a contact us link and they should be able to help confrim how much time to allow.