Responsibilities of a migrant. And who owes land?

The right to migrate is not the same as the right to join a political community. I've speculated before that the right to migrate is joined in part to land and other natural resources being common goods. One has the right to move elsewhere in order to supply for their physical needs. As a consequence, they can settle there and establish some sort of community. Because of man by nature is ordered to living in community, he should first of all move in a group, not individually or with a family. If he seeks to join another group, then he should find one with which he already has some social ties and shares a common culture, and while his request to be with them should probably be granted out of hospitality (guest-hospitality of the Greeks or what not), it is nonetheless provisional. His acceptance does not mean that he is entitled to the full rights and benefits of citizenship.

I have also mentioned the responsibilities of a migrant in passing elsewhere. Off the top of my head, I am thinking primarily of the responsibility to adopt the culture of the host community (in so far as it is not forbidden by the natural law), and to embrace its mores and language, and to offer one's loyalty to the people and devotion to the common good. If his heart does not lie first of all with his host community, at the very least he should not expect to be considered one of its own, but to remain an outsider. If he desires to be a member of the host community, he owes out of justice complete participation in its economy, as the the network of economic exchanges from which he seeks to benefit is ordered to the good of the community (of the members who make up that community), and not to the good of another community. (Hence there is a moral dilemma for those who leave family behind in their native community and are obligated to provide them with financial support, plus whatever other obligations he owes to other members of his native community.)

If he remains an outsider, he may be morally free to send money home. And it may be that he is owed a family wage for his work, and not merely a wage that will support him individually. Still, does the host community have a right to decline him the right to participate in the economy? (So long as it provides him with some means to work and sustain himself?)

A tentative response to the question I raised here, "If secular governments are unwilling to part with the territory they control, even though land is a common good, then how can the right to move (for the sake of improving life) not be transformed into the right to immigrate?" It seems to me that the claim to land and so on should first be pressed in their native country, not in a foreign country. We can look at a concrete example, Mexico, and ask how many in Mexico are forced to leave and look for work elsewhere because of the lack of social justice in that country? Isn't it incumbent upon the Mexican government to satisfy the claim to land and such, before any other political community? And if the Mexican government fails to meet its obligation, forcing another political community to do so, then does that political community have the right to seek redress/compensation from the Mexican government?

(I ignore at the moment the complicity of U.S. companies, and by extension the Federal Government, in promoting social injustice in Mexico.)