Its hard to predict when will you receive EAD based on your husband GC application. BEC is planning to clear all backlog in 2 years. Also one need to apply I140 + I485 (provided its current for respective EB category) to get EAD.
About OPT, as far as I know, once you complete your second master in accounting, you should receive another OPT for 1 year, though I am not 100% sure on this. Please check with school immigration service or someone here can comment on their experiences.