Ok, good ideas here. I should try to leverage teachers and therapists a bit more than I do. I try to be very selective and sparing with that; maybe I should work that angle a bit more.

If there are no magic answers, so be it. I'll just brace myself and carry on. It's also a bit heartening to hear that my kid isn't the only one who does stuff like this, and it is as exhausting as it seems.

Individual answers (sorry for the epic length, hope I'm hitting it all):

Early on (two years of age), we instituted the 'at least one bite of everything on your plate' rule and did leave things alone if he took a good-faith bite of a new food (as opposed to nibbling the tiniest possible micro-molecule etc). We continue with this. Even still, getting him to take that bite is often a 30- to 45-minute struggle. Seriously.

I tried artful arrangements of food a few years back, when he was around two--I got an alpha-numeric set of cake-decorator's tools to cut letters and numbers out of cold cuts and cheese slices. He would admire the letters, gleefully read the words I spelled with them, read off the cheese numbers, sometimes even rearrange them...but he would not eat them. At that point I abandoned the technique (cleaning those tiny metal molds was a complete PITA) but you raise a good point--maybe I'll have more success with the concept now that he is older.

As for dessert--we have instituted two sure things: a home-baked cookie on Wednesday (and he helps me bake them now, and he decorates them too) and his choice of dessert on Sunday. He gets these two weekly treats no matter how he behaved during the day, and no matter how well or poorly he eats. The notion here is to show him we keep our word and we carry through, whether it's about something he likes or something he doesn't. We want to be careful using food as rewards because my husband and are both very overweight. We use them, but we only give one food reward for every four non-food rewards (toys, Harry Potter chapters, supervised Wikipedia searches, etc) and are desperately looking to expand the non-food-reward options.

Also? This kid does not recognize the transitive property of food. For a long time, he would eat goldfish crackers, and he would eat pretzels, but he refused to eat pretzel goldfish crackers. I wish I was joking, but I am not. So, each iteration of a food is essentially a new food to him. For example, he now eats grilled cheese sandwiches (and boy it was work getting him to accept those), but last week he refused a grilled cheese sandwich he ordered at a restaurant because it had visible grill marks on it. (The ones he eats at home have no grill marks.) Only after a lot of coaxing did he deign to eat a quarter of it. The situation is utterly crazy-making at times.

If I ask DS what he thinks of a new food just after he tries it, he will, without fail, tell me he doesn't like it, even if it is clear by the look on his face that he likes it and just doesn't want to admit it. We deal with this by sticking to the 'try one bite of everything on your plate' rule, even for things he's tried and disliked before. (Research shows that kids need to try a food at least 15 times before they decide they like it.)

Sometimes we do give him choices of places to go, but it doesn't always work. If given a choice between a place he knows and one he doesn't, he picks the one he knows. If given a choice between two places he doesn't know, he will refuse both. We get around this by saying he's going to go to New Place on X date and signposting it and foreshadowing for a week ahead of time. (We will sometimes ask his ASD therapist to write what's called a Social Story, which is just that--a story that tells what will happen on the day.) That prep usually kills any initial refusal but he'll sometimes refuse to go on the day and we have to deal with that tantrum and get him over and past that. (sigh)

We have explained (always when we are calm) that it is important to eat a range of foods so he can grow up healthy and strong. He essentially agrees and understands but this evaporates when he's faced with his longtime enemy, string cheese, or the dreaded tofu snacks.

As for books! Will look into those titles, thank you. DS loves Green Eggs and Ham and has for ages, but its message has not sunk in. DS likes its wordplay far more than its ending. Even still--Mo Willems has the new world-beater on this topic: I Really Like Slop! DS LOVES LOVES LOVES it. We got it about a month ago. I hope its message will sink in... no luck yet.

And yeah, during all of this, we are working with him on politely expressing displeasure with food. In the last six months he became a rampant 'yuck'-er and 'ewww'-er. (Sigh again)

Ah! We have won the bathroom war, at least. Racing him there always works. (Whew!) So does telling him we won't leave the house until he's used it. He HAS internalized our belief that being late is not allowed. He's closing in on 450 days in a row getting out the door on time to go to school. Yay!