H1 to J2 and back to H1


I am currently on H1B and I will complete my 6 years in Sep 2019. My wife is on J1 without 2yrs residency requirement. Can someone please help me clarifying the below questions?

  1.   Can I change my status to J2 and work on EAD for a couple of years?2.        I want to change my status back to H1B after 2 years to utilize my remaining H1 period and start Green Card process in case my employer sponsors. To change my status back to H1,  do I need a cooling period of 1 year outside the US? 3.       Does my case fall under Cap Exempt? If yes, should I apply CAP exemption before 6years from my previous H1 approved date or I can do it anytime as I have utilized H1 for some period.