You're right, probiotics pills will be of very little help. Why? Because most pills on the market are far too low in the amount of probiotics they carry. Also, they're not all designed to survive in the stomach environment, to make it to the gut. And the strains of bacterias they carry (acidophilus, bifidus...) will not kill any fungus, but will just help keeping in check. And you're right, they won't really colonize the gut where the yeast grows.
Kefir, especially homemade milk kefir in my experience, is far more potent than that. First, it has its own antifungal qualities. Kefir is a mix of bacterias and yeasts. Some of them will directly kill the fungus and other unwanted parasites, and at the same time will colonize the gut to replace the "holes" left by the dying fungus, preventing it to come back. Probiotic count of kefir is far more important than any probiotic on the market, more than you can even imagine. The probiotics that homemade kefir carries have also the advantage to be in the ideal environment -the milk- to survive stomach acid and to make it to the gut. And it is very very cheap to make. The antifungals taken at the same time might kill some of the kefir bacterias, but a lot of them will survive as they are so numerous.
Forget the glutamine, really. It is counterproductive in my opinion. I used to feel unwell and have headaches and sometimes kidney pains minutes following its ingestion, all indicating massive ammonia build-up. On the opposite, OKG will help as it directly reduces the ammonia the liver has to process. And will provide all the glutamine (as it is a glutamine precursor) needed by the enterocytes of the gut. But I don't believe you necessarily need OKG to heal a leaky gut.
One thing that made a dramatic impact on my health, is milk kefir retention enemas. They directly provide the friendly microbes where it is needed, and will kill any yeasts present in the colon. Enemas might seem weird to most people, but when you're very sick, you've gotta do what you've gotta do. Beware of the die off symptoms though, it can be very extreme if a lot of kefir is used.