The diagnosis isn't important right now. You can pursue a second opinion if you want, but first off, contact the local school district to have him evaluated for special educate/early intervention. They'll have 60 days from the time of initial contact to get him into EI, which means he'll likely be in for the coming school year. The medical folks won't have as much advise and won't be able to help as much as the educational folks - get in with them as soon as you can and take it from there.
I recommend a developmental pediatrician. For my son, the dev ped's workup was much more extensive and helpful than our psychologist's.
I don't have much input on the diet yet since we just started it. But I did put it off for a long time just because of the pickiness - the food tantrums were through the roof and only now am I ready to deal with that!
I would also get a referral to see a pediatric neurologist. My son had an overnight EEG and an MRI to rule out seizures, etc.,
If your son has digestive problems, it wouldn't hurt to try the GFCF diet. We did it for a couple of weeks just to try all the great products that are out there now. My son is also very picky and we were able to find a lot of fun, tasty things. It was pricey and I didn't feel it was worth it for us because I didn't see a difference and he really didn't have any digestive trouble to begin with.
Try to contact a local autism support group. You can go to the Autism Society of America and see where their nearest chapter is. If within reasonable distance, contact them and go to a meeting. Ask the other parents for info. Also, call the public school district and find out where the nearest Parent Resource Center is. They will also have helpful information. Your child is young. You have time to get other opinions as above. I would also contact the public schools about getting a comprehensive evaluation for your child to determine if he qualifies for special ed services. I pursued both EI and public school evals at the same time. EI is alot faster here. You cannot get both services at once, but you can get your child evaluated by both in the same time frame.Jadon was diagnosed (although provisionally) with autism about a month ago and I'm still trying to learn and figure out everything I need to do.Welcome to the forum.
1) It doesn't sound like a very thorough evaluation. The school district should do testing to uncover specific delays, and a doctor should help you rule out treatable, medical conditions that can look like autism (such as hearing loss).
2) Depends on who's best in your area.
3) Many use the GFCF diet but not most of us. I personally would never limit my son's diet without consulting a doctor or nutritionist.