Hi Curtis....welcome.
First of all.....Congrats on your success so far. 87 points in 3 months is great!
So....the things that I would suggest...
You said you have 5 cards with CLs totaling $2800 and debt down to $1200 but instead of looking at your totals.......when you look at each debt individually, are the balances less than 50% of the CL? And yes....getting them down even lower could bring your score up a bit.
For any accts with late notations - try GW letters. Some people have had luck with these. Try seeing if you can find someone in the executive office (president,vice pres, ceo even) that has some power.
On the 18 inquiries - I have found that disputing inquiries with EQ has become VERY easy. I had probably 20 between my husband and myself and disputed them ALL off. I did that online.
For the other two CRAs....you can try sending in disputes via CM (I can tell you right now EX will be a PITA but you can still try)....just state you never authorized the inquiry.
And yes......getting an increase on your CLs can help your score too. Any of your accts that you've had good payment history on (at least for the last 6 months)......call them up and ask. It never hurts to try.
A couple more things you may want to try to get a quick boost in score is.... getting a new positive TL. The first thing that comes to mind is something like Crown Jewelers. They don't pull your CR - so no inquiry and they basically will give credit (with a decent CL like $1500) to anyone that has a verifiable job and phone #. All you have to do is make a purchase first for it to report. I just bought an inexpensive pair of earrings and made like 4 payments on them. It's almost guaranteed you will be approved.
The other thing you could do is piggy back on someone's card. If you know someone (a family member or close friend) with a positive TL (with a decent CL and good payment history) that would not mind putting you on their account as an authorized user.......that would give you a point boost. You never even have to have a card or use it and it would not impact the family member/friend's credit at all.
Well, hopefully I've given you some things to try....
Let me know if you have any more questions.
Good luck and keep us posted on how you're doing!