Can 2 siblings sell property without the 3rd's consent?

Answer 1

No. You can only sell your own interest. The buyer would not acquire full title to the property unless all the owners signed the deed of conveyance. If only two sold their interests then the buyer would only acquire a two-thirds interest. If the third party doesn't want to sell you would need to petition the court to partition the property. If the court allowed the partition a commissioner would be appointed to try to divide the property. If dividing the property is not practical then the commissioner would be empowered to sell the property and the net proceeds would be equally distributed to the three tenants in common minus the legal costs of the partition.

Answer 2

That depends on how ownership of the property was acquired to begin with.

Answer 3

No. A person can only convey what they own. One co-owner could only sell their half interest. It gets more complicated it the property is held in a tenancy by the entirety.