NTC stands for Non Traditional Character. Basically a new character will start out at a young age but for example someone with enough story points, or someone with a title starting in Expo could start out as a 40+ year old instead of a child. Doesn't really have anything to do with Wards. Exact quote from down the rabbit hole.
Non-Traditional Characters (NTCs)
The answer to the child not-yet-ready for inheritance lies in Non-Traditional Characters. For those new to this concept, NTCs are NPCs which have been 'inhabited' by a player. Put differently, imagine there's a 35-year-old NPC in the world. He has an established career, and he's got a family, land, some wealth, etc. Now imagine someone goes to the character creation screen and instead of selecting a family to join, they choose an NPC to inhabit. They become that 35-year-old NPC. That's an NTC.
As for what happens to your stuff land, titles and property (homes and such) need an heir to pass between generations. If you have a home and a plot of land but die without a chosen heir it reverts back to the Counts LMT as an abandoned plot. (Last I've heard anyway could change)
Your personal affects however like a sword and armor could be hidden in an out of the way place and picked up after you start over.
The game is more about what happens to your bloodline than just what happens to you. So heirs are pretty much needed to pass any real wealth from generation to generation. You can make it work only playing wards but it will be difficult to pass more than just what you can carry (or hide) to your next life.