UC-V,
IMO, by all means try the probiotics you've purchased and see how you do on them, however I don't think they contain enough active cultures. VSL #3 contains 8 different strains of probiotics and number at 450 billion active cultures, and was especially made for UC. You may want to consider trying that after the current Costco probiotics.
L-Glutamine powder is great for 2 things:
1) Diarrhea, take 1 teaspoon in a little water on an empty stomach, several times a day.
2) Long term colonic repair: 1 scoop ( approx. 5 grams) added to protein shake - made with almond milk. I would suggest you try dairy, wheat, gluten free too.
Slippery elm powder is great for coating the whole alimentary canal.
Mix 1 teaspoon in 1-2 oz. of water (room temp and filtered), then you can add your probiotics to it, and some honey if you like. Drink this "cocktail" 3 x per day, after meals.
Hope this helps.