The ground frozen *should* be balanced, so if one dog is getting blocked, it may be temporary as she adjusts. More meat would be good, ground beef or skinless, boneless chicken breast might not be too repulsive for you Also, you can add canned pumpkin (not pie mix, just plain pumpkin).
3% is ok to start with, especially if you are trying to put some weight on, but keep an eye on them and you may need to cut back later. I adjust mine based on time of year, activity level. After awhile you just eyeball it I give sardines about once a week, as well as eggs. I don't usually give the shell, just crack an egg over their food. I also do not feed veggies, one of my dogs can't eat them.
As for switching your cats, good luck I have never convinced mine to eat raw, but I think most people who have started with the ground mix. The texture is similar to canned cat food, which makes it easier for the picky, traditional, hide-bound little monsters accept it
The sardines will help their coats, or you could just give a squirt of salmon oil.
Have fun!