I think it sounds like Sensory Integration Disorder and not Autism.
Which is what my grandson was diagnosed with at 10.5 months. (Sensory Defensiveness.)
Your son may refuse to eat because of the texture of the food item! My GS had a problem with textures of food and the feel of certain toys. Soft toys were a problem altho now he loves them.
thru therapy and normal maturing he is now ok with all textures of material but still doesn't like some foods, like pretzels or granola...
Surprisingly, my grandson would
NOT use a sippy cup, he preferred a straw! The therapist said a straw was an excellent alternative because it strengthened the muscles around the mouth and tongue.
So, give your son a juice pak with a straw.
***Have you had your child's ears and hearing checked? If they cannot hear, they cannot talk--and don't wait. My grandson was not talking at 14 months. The ENT said to remove the adenoids and put in tubes (they were needed) and THAT DAY he started saying a few words, and then talking and hasn't stopped since. he is 4, now...and a big talker.
***Did you know that not being able to hear can make a child frightened of so many things in our world? Like loud noises, and strangers? If he cannot determine what he is hearing he can't understand the world around him. and may not be able to tell you what is wrong.
On the other hand, if he can hear properly the world will open up to him.
A lot of the issues you see could be traced to one thing, hearing and sensory defensiveness. I think you will be alright but check his ears.