We have three dogs and they all take turns being picky!
We switched last year (again) to Nature's Variety and it's worked so far because they have different formulas and we rotate. We also buy the Homestyle can food from NV and rotate that as well. We mix in a little bit of that and green beans with the kibble.
We feed twice a day and we do just have to keep an eye because two will be little food thieves and try and hog down the others!
Yorkies are known for being picky and we have tried quite a few brands prior to NV.
I know with our three, they just plain will not eat dry kibble without veggies or green beans mixed in.
When we have to give pills we put it in cheese or in little balls of bread. We have used peanut butter as well!
Good luck!