Hi Anthony and welcome. Normally, the Credit Card must match the purchaser's address info for firearms purchases. You may have to have Buds Customer Service assist if you run into issues with her CC.
2.) All certifications are referenced/checked by your local FFL Dealer.
3.) The local FFL charges a transfer fee, no Buds, unless you are picking up the firearm from Buds. Generally between $25 and $45 depending on your local FFL's fee.
4.) Yes, All CA firearms laws must be adhered to as far as waiting periods.
Cheers, stay safe and enjoy!

Hi Anthony, 1- you can use your fiances credit card, as long as it is your account you are using, so the gun will be addressed in your name, and you are the person to pick it up.
2 - Any certifications required do not need to be sent to Bud's, that is done at your FFL.
3 - The transfer fee is set by you FFL (usually $15-50) and paid there. You do not pay it to Bud's.
4 - Yes, all CA laws apply, your FFL will fill you in on any waiting periods required.
.
Good luck, stay safe, & have a great day!