I think the question is how much you view being vegetarian as a burden/a good deed that you are doing vs just a feature of your everyday life. For me, I don’t even think about it, so I don’t believe that I have the “good deed offset” issue you mentioned. But others may be different!
A second question is how much weight you give to a deontological moral system being correct—e.g. you probably wouldn’t eat factory farmed humans regardless of how that might affect your other actions because that seems immoral.
A third question is what would the replacement activity for being vegetarian be? Would you realistically replace that with something as comparably high impact (e.g. - eating a serving of chicken requires ~4 hours of ~torturing the chicken to get you the food—do you think whatever you would replace that with would be worth torturing a chicken for four hours? If you aren’t spending the extra time donating more to effective animal charities that seems like a high bar to clear.)
Lastly, you can avoid much of the negative impact of meat eating if you eat from places here you are highly confident in the good treatment of animals (difficult to do but possible) or just eat beef and bivalves (much easier). So if you do change I’d recommend being thoughtful about it like you would with all other decisions!
I think not adopting policies or helping people to immigrate would be a very tough sell, given (my impression, at least) of the overwhelmingly strong evidence of immigration on quality of life and economic growth—I was under the impression that the evidence was pretty strong on the “brain drain=good” side, though I could be wrong. An important part of being EA is being evidence based, and I’d need to see evidence that brain drain is actually bad on net.
This also seems very morally problematic—“US passport for me but not for thee” doesn’t seem like something I would be comfortable supporting ethically without very strong evidence otherwise. Forcing someone to work and live somewhere against their will seems really bad. I wouldn’t want to be plucked up, moved to a developing country, be forced to work, and told I couldn’t leave, and I’d encourage people to not do that to others as well.