Rebecca is a sister of my good friend Emilie. My husband and Rebecca were both in Emilie's wedding many years ago. Rebecca and her husband have a little girl named Charlotte Elizabeth and they are awaiting a surprise in March. Some names they like are Ella Ruth, Molly Louise and Lillian Louise. Those names definitely flow with Charlotte Elizabeth which follows the formula of old-fashioned + classic. Yes, I think of formulas for names. My kids have biblical/classic + ethnic and surname + biblical.
For inspiration I researched Charlotte and took note of the name's journey though babynaming history. I started in 1880 and watched it move over the decades, peaking in the 1940s at 59 and sinking in the 1980s to 299. It has been a constant name and it's one of my favorites. Charlotte's Web is a favorite book around here.
I also used nymbler and babynames.com to find some additional boy names by meaning. I think the boy names would all work well with a classic like Thomas, James, William, etc. I'm not usually a fan of people using the same letter but C is an exception since you could have a Charlotte and a Caroline and the alliteration isn't there.
I like to search by meaning sometimes on the babynames.com site--that's actually how we found Bennett. I looked up names that meant 'blessed' and it popped up and we both liked it. So I played around a bit for you.
Small (wee tiny baby small):
That's how I settled on Ciaran for James' middle name, it means 'little dark one' in Gaelic and he had a ton of black hair. We didn't have a name for him until he popped out. The morphine had kicked in as well so I consented to a family name as long as he could get a good old fashioned Gaelic middle name like mine (I'm a Moira).