If you have an allergy dog, all those protein sources are the exact wrong approach. Allergy dogs need elimination diets and ONE source of protein (even in treats and supplements) for 6-8 weeks to work on identifying the allergen. If you cheat with a different protein (a treat, an egg, a supplement containing beef, etc.), you re-start that 8-week clock! The vet derms say that food allergy testing is not accurate, and elimination diets are the gold standard to diagnose them.
Second, mixing kibble brands is a bad idea for any dog, but especially bad for allergy dogs. Each is formulated to be complete and balanced on its own, but mixed together, it's no longer complete and balanced because you're throwing off all the ratios that the manufacturer of each one intended. Pick one. (Fromm uses multiple protein sources, so it's not appropriate for an elimination diet IMHO.) FWIW, when we have food-allergy-suspected dogs in our rescue, we generally go to Wellness Simple Salmon because we've had better results over the years on it with more dogs than with other options -- YMMV.
Prozyme is an excellent, cost-effective product -- I've used it for years in dogs with GI issues, and I've seen it solve flatulence and chronically fussy tummies in a number of kibble-fed dogs. (Are you wetting it to activate it?) I don't know your probiotic, but does it help? Usually having a broad-spectrum probiotic is a sound idea for allergy dogs, as there's research discussed here in the past showing that gut flora and allergies are connected, and better gut flora can sometimes improve allergies. The problem is going to be the strain--there's no good research yet on which strains are best for allergies in dogs, and so it's a guessing game. A lot of canine probiotics have been demonstrated by research to essentially be frauds with no bioactivity at all though...so choose carefully. Can you tell a difference when the dog isn't on it?
Fish oil/EFA supplement is good for most dogs, as it's degraded in kibble. The problem is that there's often no quality control in pet-specific ones, and they may be degraded (worthless) or contaminated with ocean pollution or mercury. I would focus on brand known for products made with very high quality control over the supply chain (like Nordic Naturals), and read the reviews/third party testing results re contaminants. If your manufacturer has no third-party testing reports for pollution and contamination, dump them. (I don't use krill products because I'm trouble by their environmental unsustainability and impacts on Antarctic penguin and whale habits.)
Cosequin is also an excellent product (I use the RX Dasuquin in my arthritic dogs, same company) -- this company has the ONLY patented form of glucosamine/chondroitin supported by any high-quality research (this patented form has shown benefits where the drug-store OTC supplements have not). It's the only commercial form of gluc/chon I would use, given the current state of research. HOWEVER, if your dog has no arthritis, why are you using it? If it has arthritis already or has dysplasia making it likely, I'd be using Adequan instead (RX only). Have you done xrays to see whether a problem is coming?
Lastly, please reconsider buying supplements on Amazon if you have a choice. I know it's convenient, esp. with Prime...but...they've been outed selling counterfeit pet supplements very recently. You're better off with Chewy, Valley Vet, Dr. Fosters & Smith or any other authorized vendor that gets them through legitimate channels and doesn't host third-party sales. NutraMax (who makes Cosequin) has been tracking counterfeit goods purchased through Amazon and issued a consumer alert: