We've been to this OPH several times. The kids always enjoy it. The food is a bit heavy but I think that's why people go here.
So I can't have gluten, egg, or dairy which one would think would take almost all of the menu. In the past I have resigned myself to this and just taken the kids here to eat and fed myself later. Today though on the urging of friend I decided to inquire about what I could eat. The waitress sent out the manager and he kindly walked me through what my options were. He was very knowledgeable and quite helpful and I was able to get reasonable tummy friendly pancakes. He did warn me that they use ghee on the griddle and that he couldn't fix and for me that wasn't an issue.
So if you have stuff you can't have know that they can work with you to try and come up with something for you and it's worth a shot.