If it were me, I would just use the land as much as possible for my personal use and not spend a penny on upkeep or building on the land. You are using some pretty specific terms that have specific meanings (some differ even by state), but the general idea is that:
Step 1 - Define what they have...
- Tenancy in common means that while each "tenant in common" owner may own only a percentage of the land, every "tenant in common" can use the entire property. The ownership shares in the property do not have to be equal, and each owner can sell or bequeath his/her share in the property without the other owners’ consent.
This means that each of the three original tenants in common owners had a % ownership and the right to use it all. This is exactly what would be passed on. The individuals % ownership and the right to use it all.
Step 2 - How is it passed at death....
- This completely depend on state law and I know nothing about Illinois except #23 used to play there. Generally if the property is left pursuant to a valid will, the will determines who get the property of the individual defined in step 1 (i.e., % ownership and right to use it all). If no valid will exists, you have to look at state law. It will be very state specific, so just google "Illinois die intestate". That means died without a will.
With that many people involved you are pretty much screwed. No matter who owned it, someone owns it now, and it can be traced though either a will or the intestacy laws of the state. Just be glad Illinois is not a community property state or you would be adding another 12 people to the ownership count to sort through.