Can i request a delayed COS of H4+ H4 EAD right after my F1 EAD expires?

Hello, I am currently on a working on a F1 visa with OPT EAD till June 2016 under EXT. My company will be applying for the H1B in April 2016 again as my OPT EAD is valid till June 2016. I am considering switching to a H4 visa with H4 EAD. I am getting married on Dec 4th, 2016 in India. My fiance is currently on a H1B visa with an approved I-140. I am considering applying for the H4 and H4 EAD in January 2016. My fiance’s H1B extension application will be applied by her company in January as it expires in July 2016. 1) Can i cancel my H4 application for COS if H1B is picked in the lottery? 2) Can i continue to work on my F1 EAD till the H4 EAD is approved? 3) Can i request a delayed COS of H4+ H4 EAD right after my F1 EAD expires? Any light on this would be appreciated. Thanks