1. they should already have your I-693 from the medical he had abroad, but I would say still bring a copy of the DS-3025 with you.
2. if it were me I would bring copies of everything with me. plus anything that wasn't included with the original I-864 (like most recent tax return)
3. I-94, copy of K-1 visa in passport, NOA2 from I-129f, marriage certificate. potential options
4. if you have life insurance or a 401k, adding him as a beneficiary to those and providing that. power of attorney letters (medical power of attorney, durable power of attorney) for both of you, also options
i assume both credit cards have the same number? but have your own names on them? you could make copies of the front of the cards and include those are proof