I got an admit into a US school this Monday for the fall 2016 intake. I'm already living in the US on F-1 visa and have been working with a company who filed for my H1(not premium) on 1st April. I hadn't interviewed or heard from the school until last week of March so I didn't stop the H1 filing. The admit came after the lawyers had put the papers in for the work visa. This puts me in a fix as I am inclined to join the school in 2016.
1) can the company, and if so, till when can it request for the H1 visa application to be retracted, and what implications would it have on my current student visa ?
2)if my H1 gets selected, do I have to get a student visa before joining the school or the new I-20 and sevis update would allow me to leave work and continue on the student visa ? 3) if the H1 gets picked, do I have to leave the country to get a stamp again for student status, or can I study in school until and get a stamp when I leave the country during winter break?
3) USCIS advises students not to leave the country from April to October because if their application is selected, they will out of status until October. If I cancel the H1 after it gets selected, will my F1 visa validity also get revoked?

It's quite a unique situation and I can't find anything online for this kind of a situation - the H1 can be selected anytime till sept/oct and I have to join the school by July mid. Any suggestions or guidance would be of help at this point.