There are certainly some top academic D3 schools, some of the best in the country. However there are just as many, if not more D1&D2 top academic schools which offer both academic and athletic scholarship money. Furthermore, some of these schools are even public(i.e. Univ. Of Virginia or UCLA) so tuition is much lower. So if the only reason you are limiting yourself to D3 is based on academics, you should broaden your horizon(assuming you are also able to play at those other level universities).
As to your immigration related question, that is beyond my pay grade.
Good luck and come back to let us know how things turn out for you.