Things like clothing are quite easy to adjust, he'll probably prefer trackpants and t-shirts which are easily accessible.
Noises - you'll develop a habit of shielding him from sudden loud noises such as hand dryers, spa bubbles, power tools, vacuum cleaners etc.
Foods - I'd agree that it needn't be a huge focus to get him to try new foods. He might be able to tolerate trying things better when he's more settled in other ways but he's so little and probably overwhelmed that it's just one more challenge.
How's his sleep? Mine likes a tunnel arrangement, pillows under the sheets to create a cocoon, helps him feel hugged and secure. Also a weighted blanket.
Hair washing and brushing... sounds v painful but in all honesty a small child's hair doesn't need to be washed v often and even brushing needn't be a priority. I'd rather have them feeling good.
Resistance is good. You can pop a bag of sand into a little backpack and get him to wear that, or little weighted wrist bands.
Physical exertion, especially resistance is time in a swimming pool, running, scooting, biking or on a trampoline. When my boy was little we had a little trampoline in the living room for him to jump on.