DeeDee ... we would definitely do speech therapy through school no matter what ends up happening with the preschool program. DS4 went through once a week small group ST at school before he started the preschool program and the approach there was much better than EI speech therapy.
cc6 ... thanks for your experience! Your son sounds very much like our little guy! I will look into the Adaptive Skills therapy. That's something new to me!
If we refuse the preschool, we can still get speech through school. The way it works here is they offer a range of services based on his needs and we can accept all or some.
He is still 2.5 years away from K so I am considering starting him on K curriculum informally a year earlier. K is not mandatory here so one of our options is start him a year early homeschooling both K & 1st and then he could go straight to 2nd basically doing an unofficial grade skip (of course, if he's somewhat ready for it socially when the time comes). If not, then we'd probably keep homeschooling.
Here the school doesn't really get involved in anything related to homeschooling. The school "can" accept partime homeschoolers if there are spaces available but those not full time at public school do not receive services like speech therapy and such so then we'd have to go the private route for speech.
There IS still a good chance that just like with our older one, his speech will really take off in the next couple of months. He too went from 10 words at 26 months and still no sentences at almost 3 years old to speaking in full sentences and just weeks later and now close to 4.5 he speaks well beyond his years. Plus we are doing two languages with both of them, which makes it harder too.