Thank you very much for doing this. I have permanent residency, and children younger than 21 who live abroad. If I were to apply for permanent residency for them, would they be able to visit the US as tourists while the process is ongoing, or come to study to an American university with a student visa?
The answer depends in part on whether they already have B-2 tourist visas. If they do, they should be able to visit you without issue. If they don't, they would need to apply for visas and that adds a layer of uncertainty - their visa applications could be denied. Between B-2 and F-1 visas, there's a greater likelihood that their F-1 visa applications would be denied. But, with some planning, you might be able to minimize these issues. If you'd like to discuss this, email me separately.
