Welcome to the Forum. I'm not familiar with the food you mentioned so I can't suggest a substitute for it. If you browse through the posts in the Diet and Health Board here on the Forum, you'll find some recipes that might work for you.
Welcome to the forum to you and Snickers Like cnyguy pointed out there are lots of resources on the forum Hopefully you can find some ideas. Quaker’s can be picky though so it would be best to start with the food he was eating before you got him and gradually introduce new foods. Have fun!