HI S.,
So sorry you're having a hard time with you're two little ones. I think we all go through this from time to time.
Are you doing anything to promote the idea of potty training for your 3 year old? If you aren't already doing this, you might get some "potty" books to read with him daily. There's also a good video called "Elmo's Potty Time". If you aren't TV watchers you can just put a segment at a time on to see if you can get him interested in the idea of potty training.
As far as the eating is concerned, I would broaden the things that you are offering him. It has been said that kids have to try a new food something like 10-15 times sometimes before they like it. At three you can have a conversation about it and tell him that each day you're going to give him a new food to try and make it into something interesting for him. I would give him enough variety on his plate that he can find something to eat, but I wouldn't cook special dishes for him. And I wouldn't continue to cook the same old favorite. Don't make it a battle, but he'll try new foods and he'll eat when he's hungry.
I disagree with the wrestling, depending on how it's done. Adults playing physically with kids is really important and valuable, but should be done in a way that the child learns what limits and boundaries of play are. Also your husband needs to let your son know that the wrestling type of play is only play that he can do with Daddy ( or you if you do it with him) , and it is play that you both have to agree on. (This keeps him from feeling like it's ok to wrestle with the baby or jump on your back when you aren't ready for it.) I used to tell my son that it wasn't time to play like that right now and give him a designated time we would play. So in your case you might say, "No Joe, it isn't safe to play wrestle with the baby. That play just for you and Mommy and Daddy. When baby goes down for him nap you and I can play wrestle. For now let's go outside and I'll chase you." You and your husband might also check out a book called "Playful Parenting".
Good luck!