I am in the camp that if I don't plan on using a card, I am closing it out. They will report for up to 10 years after closure. You should always have the card open at least a year to make good with the bank, especially if you may want another product from them down the road.
Utilization is a key factor and with so few cards, maybe just keep them open. Discover (assuming you have the IT and not the Miles) has rotating categories that can be useful. Disney run promos and discounts from time to time, plus in park perks. If you want to trim, maybe just the Citi and keep everything else. I assume you fly Delta and can utilize the points/perks.
I have done massive closings in the past, like 5 in one day, and I didn't see anything negative in regards to my score.
Just my two cents....but more importantly...
CONGRATULATIONS!! I'm sure that will be a huge weight off your shoulders.