Anytime you enter a project with multiple formats there's a few questions you need to ask yourself.
Most importantly is what your output or destination format will be and what that entails.
HD or SD?
Web, TV, Theater?
Your eventual framerate and resolution are what you're trying to nail down as there is no use in upresing everything if you end up only burning out DVDs.
After you know that, you need to know resolution and framerate of your source footage to make the correct plans to get them in the most convenient format for your destination format.
It seems like you already got most of that but I figured it was worth posting.
As for where to go from here, what is your ultimate destination and what format was shot with the Canon? Luckily what you have right now will play well with each other framerate wise.
Was the DVX stuff shot widescreen or fullscreen?
As far as "capture/playback" everything you have is a digital format so you don't actually have to use an I/O device to access or convert any of it. Hardware manipulation is typically better (a Teranex type device would be well suited to this
http://www.blackmagic-design.com/products/teranex/) but none of your cameras have a digital output so you'd either be using a computer and I/O device (the I/O Express would do this) to stay all digital (extending capture time) or be forced to use the digital to analog converters of the cameras which typically are not great. Because of this inherent loss, I'd just take the files and use software to do the format changes. Since you're dealing with the same framerate family (hopefully - those Kodak cameras can be weird - it'd be worth running
Mediainfo on the files to find the true framerate), there should be no noticeable difference.
Ok, now for your actual questions:
1. Shouldn't matter as your framerate conversions are simple. I'd suggest framerate before upres (though again, depending on output you may not need to upres).
2. I know the Konas can, I've never used the I/O but I'm assuming they can. Of course, this means a weird process of playing out and capturing what is already a digital source in which case I'd do a software conversion.
What editing software are you using?
