To best predict what could have happened if Article X had not been removed from the Treaty of Guadalupe Hidalgo, the response would be:
Tejanos living in Texas would have been able to keep their land.
Article X originally included protections for property rights, specifically for the landholdings of Tejanos and other Mexican nationals. Its removal led to many Tejanos losing their land, as legal protections were diminished, making it easier for Anglos and others to claim those lands.