OK, here's some technical info.
The Play Store installs two different versions of the Wallet 2.0 app, depending on whether you present yourself as an NFC-pay supported phone (via build.prop values) or not.
If you change your build.prop to be, say, the Sprint Note 2 (SPH-L900 t0ltespr) and then install Wallet from the Play Store, you will get the NFC-pay enabled version. All other phones get the "castrated" version.
Now, on Note 3, even if you do that, there a few things Sucksung/T-Mobile did in the stock ROM (completely reversible) to make NFC-pay on Wallet not work.
First, they removed the Wallet signature keys from /etc/nfcee_access.xml, so Wallet will complain it doesn't have sufficient privileges to the secure element. That's fine - you just add the keys back (get them from any AOSP ROM), and boom, Wallet has access to the secure element again.
Then, there are a few other bits and pieces of system software (libraries and kernel modules) that I'm trying to figure out that need to be in place for Wallet to work, as right now it just FCs. If not me, then someone will probably beat me to putting together a "fix" ZIP package that will re-enable Wallet on the stock ROM.
This problem, of course, will not be present on any AOSP ROM as all the required bits are included in those by default.
Also, remember Wallet 2.0 no longer includes a root, region, or carrier check, so "Wallet Patcher" plugins for XPosed or anything like that are not required.
The way to set up NFC-pay enabled Wallet 2.0 on an unsupported device (with a ROM that hasn't been carrier-castrated to disable NFC-pay):
1. Change your build.prop to masquerade as a supported device (e.g., SPH-L900 t0ltespr) and reboot.
2. Go to Play Store, install Wallet.
3. Launch Wallet and set it up as usual. Once it finishes and you see "Ready to Tap and Pay" undearneath your Wallet balance, you're good.
4. Restore your build.prop to its original values and reboot. Wallet NFC-pay will remain working.