I was finally able to unblock this by actually finding the Google Wallet support line here: https://support.google.com/wallet/business/contact/phone, where I was able to get someone on the phone in minutes to help me figure out the issue here.
It turns out that at some point in the past, I had created a Google Checkout account for my business (which is how the forms were prefilled and I already had a merchant account), and a pre-existing Google Checkout merchant account is incompatible with a new Google Wallet merchant account.
There are two solutions to this, according to the person I spoke with:
- Use a different Google Account that doesn't already have a Google Checkout merchant account to create your Google Wallet Merchant Account, which you can do immediately.
- They can migrate your account for you (and you'll have to contact them as I've listed above), but this takes 2-3 business days.
I hope this proves to be useful for someone else.