My passport expires in February 2018, extension of stay and workpermit end March 2017. What would be the best and easiest way, first extend passport (till 2027, so miss out on almost one full year) and after that apply for extension of stay + WP till March 2018, or apply for extension of stay + WP with present passport? If the latter, would I get till February or March 2018?

Your extension of stay would end on the date your passport expires. That has been the rule since August of 2013.

Thanks.