-If the child is adopted by an non-immigrant visa holder, e.g. an H-1 holder, then the child can apply for the B-2 visa to enter US to stay with the adopting parents, and this is also temporary, isn't? Also, many nonimmigrant visa holders who may have been in US for several years (>2 years), such as H-1, F-1, J-1, L-1, etc., are still temporarily present, aren't they?
Of course, nothing is 保障 for any visa application by any people, including regular people. What we discuss here is the possibility on regular base.