Its not complicated at all....in my case after doing some communication with International Student Affairs, Office of graduate Studies, and the department i got enrolled in; it turned out that my official legal status will still be H1B and International Student Affairs do not have to issue I-20 and F1 status since it will automatically discontinue the H1B if applied. So the office of graduate studies enrolled me as a grad student i.e. gave me an official admission and i went from there. Rest is same as a typical international student which involves non-resident tuition. for info. regarding how to manage tuition fund and research hours funds, you can ask me later when time comes.

Good Luck, u gonna be pretty busy. having GF in long distance will make it worse.