Oxbow shouldn't be fed as a main diet. It can be given in addition to a high quality well balanced feed.
There have been a significant number of reported cases of mice dying or failing to thrive when fed primarily on Oxbow.
Seeds, nuts, and pasta shouldn't consist of the entire diet. Everything I said should be fed as a mix in order to gain a balanced diet if a proper lab block cannot be used.
If bread is given, it should be whole grain. And it really depends on the seeds, nuts, or pasta.
There are good seeds and bad seeds. I.E. Sunflower seeds should only be given as an occasional treat. Too much fat as mentioned.
Flax seed, horse sweet feed, sugarfree cereal, millet, and wheat pasta are examples of good foods. But Like I mentioned, it has to be part of a mixed diet and not given alone.
And yes. Oatmeal is good.