I feel your pain. I've been through everything you're experiencing now and I am now 100% cured. So I hope you take what I say seriously or at least look into it. I know what's missing. The reason you aren't seeing improvement is because your gut hasn't healed yet (your instincts about leaky gut are correct).
Did you see any improvement after eliminating all those foods? If you did it means your gut has healed a little, but not all the way yet.
Here's what's missing in the order of most to least likely:
1. Low stomach acid levels, hence reflux (take betaine HCL with pepsin to restore)
2. Drink bone broth every day for the collagen to restore gut lining
3. Eat kefir, kimchi and or/sauerkraut for probiotics (probiotic supplements are lame)
4. FODMAPS (check them out)