Sure, you can make bread with just whole wheat flour (and add the multi-grain cereal) and no sugar.
I make a ww bread, all ww flour, water, yeast, and a T of orange juice concentrate. The King Arthur Baking book said the orange juice they add helps the flavor of the WW flour, and they tested that with consumer groups and found it to be true. I tried it and it is better with a little bit of orange juice. You can't actually taste the orange juice, it just improves the wheat bread flavor.
If your taste buds are not used to eating plain ww bread, you might miss the sugar but it certainly isn't necessary structurally or chemically to get a good bread.
We store it sliced and frozen, serve it toasted most of the time. The usual star of bread or toast is what you put on it, tomatoes, puree/jam, avocado, or make it a sandwich or to serve a burger on.