While I have not tried using a modern front loading machine; the traditional answer is no - it will lead to delamination of the PU coating inside the bag.

I would love to hear from someone who has tried a front loader.

No. The whole bag is made out of nylon.

You might be able to depending on your MEC store - I thought I saw a bunch of replacement straps in the area where they have replacement buckles and D-rings for sale. It's not listed online, but check out your local MEC. Even if they don't, you can pretty much rig one out yourself with two clips and some two-inch webbing.

No, these duffle bags are not waterproof. However, if you look in the Watersports section of the website, you'll find some that are!