Well I didnt know all that stuff and I would prompt you to write it if I knew what to say...
"...that will fit my 10 and 12 year old daughters as well as my soon to be wife." At first I pictured a bike long enough for 4 people... Ok, read slower... So seat height adjusts, and top tube removes? I wish good tandems were more common. And good vintage ones. I never heard of a 3spd tandem; someone someplace must have tried it.
Hilly in New Jersey? Do they have nice bikeways there?
It has a rear top tube that can be removed which allows for a very wide range of rider sizes... have seen 5 year olds riding on this design and it will also seat much taller adults.
It is an older model but is a custom built frame that has never been built up... will be sending it back to add braze ons for everything from bottles and pumps to disc brakes and will run a 24 speed touring set up and it will be used for some long rides as well as rides about town.