[cypher]

It would be ok to mix some Harry Hamster in but Burgess really is better for hybrids really & you may find Bambi doesn't like the biscuit type pieces in HH.
I think giving a few extras as treats (in moderation so you don't upset the overall balance too much) would be good, hemp, flax, pumpkin seeds (preferably in the shell) & buckwheat are all healthy additions they usually love.
Peeing in the food bowl is a way of marking it as theirs! It is more commonly seen in new young hams & they tend to grow out of it, throwing it away will make it worse, I would leave it & scatter some fresh food around the cage every couple of days, don't keep topping it up if it hasn't been eaten as that encourages them to be picky.

ETA I meant to say pasta is not an ideal treat for a diabetes prone species, personally I wouldn't feed it at all but if you really want to it should be a rare treat.
Stick to a good variety of fresh veg, low sugar, rather than things like pasta.