Raw and kibble don't digest at different rates, and freezing will not kill bacteria, only parasites, which is usually only an issue in wild game. If you're feeding a good variety, supplements shouldn't be needed. Organs contain essential vitamins and minerals, so having a good rotation will cover bases. Only secreting organs (liver, kidney, spleen, brain testicles etc) are fed as organ; heart, gizzards, tongue, lung, tripe etc are fed as muscle meat, because they are made of muscle.
You could add anything really, a friend adds fish, eggs, chicken wings, chunky minces to her kibble. Any vegetation is better off being blitzed as it is hard to digest cellulose, and will go straight through. You could add things like spirulina, greens powder, mushroom powder; I mix with flaxseed oil and freeze in molds, and pop one out at meal times. I also make bone broth and kefir and freeze as well.
Whilst grass fed is better, it's fine to feed whatever you can get. I would double my budget if I used grass fed, so I stick to my current supplier. I also don't balance every day, but over a fortnight. The only time I would bother balancing every day is with puppies, and even then I was a bit lax. I find it tedious and have even been doing prep daily instead of making them all on one day and defrosting during the week.