Hi Jen,
I am an educational advocate for children with special needs.
The other Moms have told you the answer, some do, some don't, but in private school you may also have to pay for therapy. It is also possible that he could still get speech through your district if he attends private school, because the obligation to serve him does not end if he is enrolled in a private school, however; the school may say that they cannot serve him appropriately in that enviornment, and if they think that he can only be served appropriately if he attends public school, then you are in a take it or leave it situation and the obligation ends if you put him in private school and refuse the IEP.
From you post, my gut says that you are better off in a public school because he has two issues. He is not a speech only child, and you will not be offered OT unless he is enrolled in a public school and receives special education because OT is a related service under IDEA and speech is an educational service that does not always require an IEP. You will probably not find OT in any private school.
The very best advice I have for you is to take your son to a Developmental Pediatricain and have a full evaluation done. If you have already done this, great, but if you do not have a private evaluation that you control, then you are in a very weak possiton. You should NEVER know less than the school district about your child. The cold hard fact about special education services is this: parents must suplement public services with private therapy if they wish to maximize their childs potential. Schools are only required to make your child "functional" and give him a "basic floor of opportunity" and you want so, so, so, much more than that for your son.
I am glad that you love your son's program, but protect him and protect his future and get the evaluation done. You don't know what you might be missing, and you also need to have a way to confirm that he is getting everything he needs and that he is really making progress. You don't want to get a few years in and find that he needed something he did not get, or that the progress you thought you saw was not as much as you wanted for him. Early is best, take full advantage of his age and get him more, rather than less, even if you have to pay for it. And by the by, the word "BEST" is at the heart of all my advice for you, the school is not required to give him what is best, only what is appropriate, you want what is best-confirm that he gets that by owning a private evaluation that is far more detailed than anything the school provides and then make sure that he gets all that the Developmental Pediarician recommends.
Developmental Pediatricans can be found at your nearest childrens hospital, and they will refer him to speech, OT, PT, hearing, geneticists, ANYTHING that he needs to get the full picture, and then they will put ALL of these evlauations into one comprehensive report for you. It is worth the time and the money.
M.