How many sailors belong to a Section vs. a Division in the U.S. Navy?

LHD Commanders (Amphib) are Captains (O6) Phibron Commodores (In-charge of LHD, LSD, et al are also O6).

I'm not sure how that affects the rest of your graphic, but many of the LARGE ships are O5/O6 level. So the Captain will be a Commander/Captain depending on the size. I know the USS Essex (Wasp Class), is a Captain, but I believe the rest of the ARG was Commanders.

On a submarine, you've got a division which is a functional element that consists of sailors with a specific rating, or job specialty. I was an Electrician's Mate and worked for E-Division. We typically had 9-10 enlisted (E-4 to E-6) And one Chief Petty Officer and an Ensign or LT(jg) as a Division Officer. There were 6 divisions in the Engineering Department, the Engineer (Dept. Head) was a Lieutenant Commander (O-4). Department heads on a Submarine (LT or LCDR) are Engineering, Navigation/Operations, Supply, Weapons, with a LCDR as Executive Officer and a CDR as CO. A "Section" on a submarine usually refers to a watch section underway, or in port. It is the group of people you need to maintain operations, security, etc. at all times. Underway we normally had a 3 section watch rotation, 6 hours on watch, 12 hours off. This would be a mixture of personnel and ratings required to operate all function of the ship.

It simply depends upon the size of the ship and its required ship's company. Department and division are often used interchangeably on a ship. I was a Quartermaster in the Navigation Division, though it was often referred to as the Navigation Department. On a WWII destoryer, my first ship, we had a LTjg as department head, one E7, two E5s, two E4s, and two non-rate strikers. On a carrier later, we had an O5 division head, O3 assistant, one E7, two E6s, about four E5s, ten or so E4s, and about a half dozen E3s and E2s. We were one division, and, again, no sections per se.