Kaytee food and treat products are poor quality overall
I definitely wouldn't recommend using their products at all other than the Clean and Cozy substrate(only the unscented type)and certain toys.
Yogurt drops are not good for any hamsters as they contain dairy(which is questionable at best for hamsters,since they don't digest dairy well nor is it a natural food for them).They're also loaded with sugar that isn't good for any animal let alone diabetes prone hybrids,so you'll need to find a bigger variety of healthy treats.
Burgess contains mealworms so you won't need to add mealworms with that,as mealworms are a high fat food that need to be fed in moderation as is provided in the daily diet with Burgess.
Make sure to be extremely careful with any food or treats.There should be no BHA/BHT/ethoxyquin(can be labelled as E&C approved antioxidants or similar variants in UK products so be very careful when buying UK products),unspecified biproducts(including digest,derivatives,meat and bone meals of any sort,and animal or otherwise unspecified liver),or artificial dyes,sugars,etc.
Diabetes Friendly US Dog Biscuits and Crunchy Treats(From Chewy)
That would be a good starting point for some examples of good treats from sources other than hamster specific treats,as long as you make sure the company making them is reputable.There are other places to look for good treats though,for example if you were to look through the whole dog treat section of Chewy there would most likely be even more potential treats.