I'm back in the game!
Okay, I concur with AmmaUltman: Crysta works for me. My path was the following:
1. Log into Square Enix Account Management at
https://secure.square-enix.com/accou...n?cont=account . Under Payments and Service Fees, click Add Crysta. (Or, in Mog Station, under Square Enix Account Settings, click Add Crysta).
2. I just wanted enough for one month (I plan on trying regular credit card again next month), so I chose "Specify amount of Crysta to add to your account" and put 1500. (Note, you actually only need 1499).
3. On the next screen, you can choose either Credit/Debit card or UltimatePay. Credit/Debit card simply spits out the same old 401 we've come to know and hate. UltimatePay worked for me!
4. Within UltimatePay, you have several options. I went with the plain credit card option, and used the same credit card which SQEX/Mog Station keeps rejecting with 401/601. Guess what, UltimatePay accepted it.
5. Back in Mog Station, the 1500 Crysta I bought showed up immediately. I was able to subscribe for 30 days of standard service.