OPT or H4? help please!

I and my hu*****and will both graduate in Augest. Now we are both F1. He is going to get his H1 aroud July. Is there any conflict if he get H1 before he officially graduate as a F1?

I plan to start work next year. I am wonderding which to use between th F1 and H1 gap, OPT or H4? Again, if I get H4 in July before I officially graduate. Is it ok?

Another queston about OPT. If I dont use OPT right now, do I need to attend another school to use the OPT period? Do I have to apply for OPT while I am in school?

Thank you very much for your help!!