I decided not to go for the AU on the Firestone card, since I don't think the $2200 limit is worth adding a 2 month old account into my AAoA. Especially since I just got approved for a Victoria's Secret card today! 
Did the shopping cart trick, no HP. It's not much, just a $750 limit, but at least it's my own account! And it's a card I'll actually use and benefit from. Seeing that approval screen for the first time in 6 years felt pretty damn good!
And my dad is going to let me transfer $1000 of my balance to his new Chase Freedom (which I'm an AU on). That will drop my Citi Forward utilization from 90% to 70%, and puts the Freedom at 18%. Still lots of work to do, but that definitely helps! I might be able to convince him to transfer more, once he sees that I'm making the payments on time.
I also went ahead and mailed a GW letter to Citi this morning...I decided the benefit of potentially getting the lates removed outweighs any possible risk. And I feel like I have a good relationship with them, since I have several student loans dating back to 2007-2009 that have always been in good standing, and my CC has had perfect payment history over the past 6 years other than those two months. I'm not getting my hopes up (especially for the first attempt), but it's worth a shot.