H4 extension with future Date h1 approval


i am currently working on h4 ead which is valid until feb 2020. i have filed my h1 b which got approved from date that current H4ead expiration date is which is feb 2020. Can i file my h4 and h4 ead extension now as my spouse h1b got approved and still continue working as my h4 ead is still valid until feb 2020 and i have h1 b to fill in the timeline until my h4ead gets approved as it takes longer time.
Also, can i go for stamping to mexico or canada for H4 and comeback and apply h4ead which will save some time. My situation is i never got stamped on h4 before as i filed my Change of Status from H1 to H4 being in US and the only stamping i have before is on H1b visa. Do i need to travel to home country to get the H4 stamping done.
Appreciate your suggestions.