I picked up a little terminology in my research on the body suit, and it comes with some good news. Here is an excerpt from stretchy.org:
"Raglan sleeves are a sort of sleeve used in sportswear - the top of the sleeve continues all the way to the neck. This contrasts with dress-shirts, whose 'in-set' sleeves stop at the shoulder. The raglan sleeve is easier to draft and sew."
So now I have the name of the type of sleeve I am looking to make, and it is very good news to learn that they are on the easy side of things to make. Awesome.