Just got off the phone with a Citigold rep, so here are some points for reference:
* The $750 spend requirement on debit card must be signature-based. Any pin-based transactions won't qualify for this requirement.
* I had no problem using a credit card to fund the initial amount (I did $1200 = 1200 UR points on Chase card assuming no cash advance fees) just now over the phone. They would not take Amex card, but Visa/MC is fine. These points will nicely offset any debit purchases that I will be making
* I got the offer email last month because I have the AA amex card. I signed up for the account on 3/29 before the 3/31 deadline.
I will post in this thread in June/July once the miles post. So far no fees have been assessed yet.