This sounds like a train wreck of a home vlog and Jenn has been spending her miserable life reading here.
I want to make his costume, I don't want to print out something or get from etsy. Jenn, your kid is old enough now and seemingly has friends...don't let him embarrass himself. Especially in a school where families have money. No one is going to have a poorly made homemade costume.
Why not this, you are always claiming your child is sooooooo smart. Explain to him, Jackson Storm doesn't have a costume, but look, his friend Lightning McQueen does. How cute is this...maybe get all fancy and replace the kid in the photo with J$ head so he can see himself.
Or....and this something you are going to have to learn as a parent, so it give you the opportunity to practice. When something is seemingly impossible, you offer another choice. Look J$. Hotwheels are your absolutely favorite. You have 976 Hot Wheels cars. YOU can be a Hot Wheels!
Didn't he love Mario last week? Another option to present to him.
I'm embarrassed for your son, Tim and Jenn. I'm embarrassed for all the shit (pun intended) you put out there about his life. Buy him a race car costume, design his shirt/hat/pants yourself It's the best of both worlds and kids won't be talking about him for the rest of his elementary school life.