I am an educational advocate for children with disabilaties. If you son qualifies, he probably needs the services they provide.
You may be surprised, these are not wearhouses for kids, they are classrooms, and your child would have an IEP that was based on his needs. The classrooms are not disabled, children have disablities of various kinds, he may be one of the higher functioning children there, but that does not mean that he will suddenly become less so if he interacts with children who are of a lower function. Be careful with your thinking here...you may find yourself defending why your son should be in a program at some point in time, because the parents of the "advanced" kids fear that he will hold them back. It really does not work that way. The children who benefit the most from being with kids who have diverse needs are the most functional, at leas that is how the data shakes out.
At this point, it is a moot point, unless he is diagnosed with a qualifying disablity by the developmental pediatrician, or is able to qualify as "noncategorical" which simpley means that the school sees that he needs the services, and does not have a diagnosis, and in that case, you have a whlole lot more to be concerned about than a minor delay in speech and motor skills. ECI is not the source you should be depending on to tell you what your son needs and does not need, and really, neither is the school district. You should never know less about his needs than any public agency (both are funded through IDEA.) Get that private evaluation, then supplement any service he gets from the state with private therapy.
If he does not qualfiy for a full program, he may qualify for speech, but not OT. OT is a related service to special education, so he must be in special education (fhe full program) to qualify for OT, even if he needs it. So, you should absolutely get him private OT. Speech is an instructional service that he may qualify to recieive without qualifying for special education.
I am going to say something very frankly, and that is that children with mild delays now tend to have greater difficulty, when they have difficulty, than children without those mild delays. If you have the chance to get your child into a special education preschool class in the local elementary school, and you turn it down, you may very well be kicking your self in the first or second grade when you are asking for help and nobody sees anything wrong. If you get in on the ground floor and he does not need it later, he can be dismissed from special education, but there is probably little chance that your son would be admitted to special education until the end of 3rd grade, even if he needs it, because that is going to be your next best chance to show that your son has an educational need. It is a pattern I see played out over and over again as an advocate. If schools offer, your child needs what they offer, and then some, so take it.
Log on to www.wrightslaw.com and learn about school advocacy. This will be a very helpful site for you as he enters school, especialy if he has more than minor issues once he starts learning to read and write, and especially, once he needs to write and read to learn.
And, as for my own experience, I have one child who qualified for these serivces. She did great, and the teachers we had in preschool programs for kids with disablities were some of the most caring, best educated, and most experienced we have ever had since.
M.