Am I right that that is the US equivalent of 9 ounces of milk? That's alot, and if it's full fat milk it's very filling. I'd cut that back to 4 ounces IIWM, so he isn't so full. He has his milk upon waking, then I'd offer him food 45 mins later, and again I'd put several things on the plate.
What would happen if the bread sticks had a little side of apple butter? Or cheese dip? Anything to engage him and make him curious. I'd say nothing, but put out the breadsticks, pick one up myself, dip it, eat it, smile, and walk away.
ETA....I'd do this in a neutral place....a new place like his own table. Maybe the tray of the stroller when out.
Since he seems like to like crunchy things, that is where I'd try to expand. When you say biscuit you mean cookie, yes? I'd make some hearty cookies, oatmeal raisin or apple cinnamon cookies, or peanut butter cookies, at least then I'd know he is getting a new texture, and it's wholesome.