When they recently desecrated the American flag, and made claims to this land as their own, they were no longer sojourners or foreigners passing through the land, but they had at that point become invaders.
Your scriptures about Abraham might be fitting if you were to argue that God intended to give the Southwestern United States to the descendants of Montezuma as an inheritance. That appears to be the desire of many of the illegal aliens who have recently come north.... To claim this land... MY Land... as their inheritance.
Nonetheless, they are still aliens....legal or illegal is not specified in the bible. Be sure to entertain LEGAL strangers because some have entertained angels unaware of it.
That Abraham's descendants were destined to take over the land really has nothing to do with the treatment of aliens. After entry into the promised land, Israel was to exercise extreme hospitality with aliens. NO ONE suggests that God's reason is due to His plans to dispossess Israel of their land. (Who knows...maybe the preterists teach that???)