Just to be totally different grin, I'm going to mention homeschooling. My son went to 2 years of PS. We tried to get him into a gifted magnet, which is very much a MG school anyway, but they do have the terminology and training. He hit the ceiling of their screening test, but still didn't get in (chose by pure lottery once you qualify). Hindsight, that may have been karma.

We are starting our 4th year of homeschooling, and it has been a wonderful fit for both my kids (My son is 10, my daughter turned 7 this summer). It has given them time to work our some asynchronous development and really dive into topics as deeply as we can. It's a year to year proposition here, but it has been wonderful for us so far. The big piece with that is finding like minded community and resources. My kid's started music lessons as preschoolers and that was a great outlet for them too.

I agree with many of the other thoughts here. I think for a child reading at 2, you're going to have a hard time whatever you choose. There are advantages and disadvantages to any choice. I also don't think you should make any early judgments that your 16 month old is going to have more challenging educational needs than your older.