Everything about boats is a trade off, easily packed inflatables won't track as well as a hard shell keeled boat, folders are better at tracking than inflatables but a solid keel is always the best.
Cargo/people capacity, the longer and wider the better, which also means heavier, slower and might need a trailer. Narrow and long is easier to paddle and will be faster. Long is harder to turn, short is easy to turn and they will without any real effort, so they don't track well.
A 5 year old has no business in a boat by themselves on any navigable waterway, period! Maybe in their own boat tied to Dad's boat, but that's really not a good idea for any distance.
I'd suggest you first define the waters you plan on paddling because that will dictate the best boat. Example; while younger, stronger with lots of energy, take on a string of faster rivers, shorter boats, like 8, 10 10/12 foot yaks. Later, taking on the Ohio River or Arkansas, slow big waters, I'd take a Freighter Canoe, 16-20 even 24 footer and for me, I have a large trolling motor as well.
I'd plan my trips to the waters best suited for the boat I was using at the time. If you don't have a boatyard available to you, sell the boat used on those waters already traveled and buy one for the new challenges.
My Zodiak was a fun boat by itself, the dingy for the Sea Ray Sunchaser.
You don't want to try to make one boat do it all, you won't be happy; portage a 75 lb canoe for a mile or two and see what you think. (hauling everything else as well).
Your skill level dictates which is safer, a canoe or a yak, I prefer my 16ft Old Town canoe, heavy, still waters to heavy current that tracks well, day or weekend trippers. I also liked playing with my Pamlico 16' double holer', even had a sail rig for it.
Bought that Pamlico to take a trip in, it was to be for a non-profit fund raiser, dollar a mile. From our City lake, to the James River, to Table Rock Lake, then through other lakes along the White River to the Mississippi and on to the Gulf. That yak with the sail would have been a great trip, but the non-profit took a different event.