S.C.
It's perfectly normal for him to want to nurse less since he's eating food. My daughter is 7 months old and our schedule goes something like this
Cereal mixed with Stage 2 baby food fruit for breakfast
1/2 jar Stage 2 veg and 1/2 Stage 2 fruit for lunch
Same for dinner
She nursed before her breakfast, once between lunch and breakfast, two or three times between lunch and dinner, and a few times at night. She doesn't nurse for very long at a time though. BUT...my dd is a peanut compared to your guy. She was barely 13 lbs at her 6 mos checkup. Your guy could probably eat a full jar of fruit and veg at each sitting.
I wouldn't worry too much about what you're feeding him, unless there is a history of food allergies. All of your baby foods should be "safe." You can't give children under the age of 1 honey, Karo syrup, peanut butter or eggs, but other than that everything is fair game. If he has 7 teeth, you may even be able to start him on regular table foods as long as they are cut up itty bitty and very smushy.