My 2-year-old has many weird behaviors. He is very affectionate with family members he knows, but not at ALL with family he doesn't know, or strangers. He toe-walks, head-bangs (usually in his crib when trying to get to sleep), body rocks, has a definite language delay (has a few words that he repeats), will pull us to what he wants (grab our hands and pull us to the fridge if he wants some juice, etc), he understands language much better than he speaks because he will respond and seems to know what we're talking about maybe half of the time. He has bad tantrums (but is not aggressive, he just cries and throws himself on the floor etc) about "stupid" things, will cry hysterically over "stupid" things like his fav show ending (he doesn't watch tv all the time but we let him watch his "Yo Gabba Gabba" sometimes), he LOVES music, even classical music - we taped Classical Baby on HBO and he will sit entranced OR he will "dance" like the cartoon characters, or spin, etc.
Diagnosis or not, their are some health red flags I am seeing from your behavior description. Head Banging and toe walking are indicators of bowel pain and/or discomfort. Body rocking as well. They head bang out of ability to tell you they hurt or are nauseated or they have craps. Toe Walking also occurs to relieve the pressure on the bowel - check to see if he does it right after he has a bowel movement-if not or it is random - clear indicator of bowel issues. Tantrums over "stupid" stuff - non violent - artificial food colorings, gluten and casein in tolerances cause this as well. Staring at the TV, fans, moving objects for extended period of time is soothing - distracts from discomfort in the body. Think about it, when nauseated or feeling sick -people zone out to the TV, movies, and want to be by themselves more than not. Spinning - form of stimming.
So you have options - label----does your state cover for Autism in your Healthcare? IF not - it that diagnosis can cause your insurance premiums to be higher if you switch insurances. You do not need this diagnosis to get speech, ot or PT. A simple script from a ped can get you that. He is young so the label isn't necessary for school IEP coverage yet.
Have you heard of a DAN! clinician? They work on the medical aspects that cause the behaviors - they will help heal the bowel, help identify if you are dealing with any deficiencies or allergies. They will work with you to identify if he has yeast overgrowth in his bowel or strep, if he is processing food correctly and more. Many alternative doctors address this as well as they want to heal the body not just treat the symptoms with a "bandaid". I would strongly consider getting him on a gluten free casein free diet immediately. This is a very easy step to take and many see results or changes in behavior in just a few weeks time. Do not use Soy milk - similar make up to casein.
If you don't mind - let's talk poop. I am going to assume he is either a constipation kid - not pooping 2x a day -soft solid banana chocolate pudding color or he has explosion diapers sometimes a lot sometimes random or they stink or dented as in more square shaped.
Bock's books are great so is Children with Starving Brains. Also consider checking out www.tacanow.com and signing up to have a mentor - you do not have to have a diagnosis. www.generationrescue.com also has an option to sign up for an "angel" . All of these are families who are dealing with what you are dealing with.
Whether it is "autism" or not - he has some medical stuff that should be looked into. If you want to talk off list, just PM. More than happy to help.