Can Android Device Manager remotely erase my stolen phone's data AFTER synced gmail account's password has already been changed by me? My android phone has been stolen. The thief took out the sim and immediately turned it off.My Gmail account was synced to it and I tried to remotely ring,locate and erase data using gmail on PC.However, since the phone was off and having no internet connection, the access was being continuously denied.When I tried erasing data remotely, a message appeared "Request sent". After that I changed the password to my gmail account that was synced on the stolen mobile android device. Now I have the following concerns:
1) Since request for erasing password was already sent before the password was changed by me, does this mean that whenever my phone will be turned on, the android device manager will wipeout/erase all data or will it show an authentication error since the password has been changed and gmail is no longer synced.

2) If I ask the network service provider to block my phone, can it still be traceable by the imei number?

3) Any other information as to how to get my phone traced back or atleast erase all the data? (I have the Imei number with me)
1) The phone is still tied to your Google account, it just can't sync any data because the password is incorrect. ADM will still issues the Erase command, and if successful you will receive an email with a message noting it was received by the device and it's approximate location if available. The fact that you changed your password after the fact is not relevant. (I do not have a reference for this, it is from practical testing)

2) No, the service would have to be active otherwise the tower blocks communication to that IMEI, thus it cannot locate it. That said, even if the service is active the carrier likely would not reveal it's location even to law enforcement without a court order and that is almost impossible to obtain for just a stolen phone. 

3) No, sorry... Once you no longer have the phone in your possession your options are pretty limited, what happens next depends on the phone and the Android version. You have pretty much done all you can do. 

Most likely the thief performed a factory reset and all your data is gone anyway, the information on a device is rarely what a thief is after. Their primary concern is a quick turn-over of the device for a cash. Best case scenario at this point is you had a newer phone with Marshmallow and FRP will make it worthless, next worse would be they were able to bypass FRP or it was an older device and they got a few $$$ for it, and the worst case scenario (and least likely) is they were able to access your device and you have all your credit card information, etc on it locally and they hit pay dirt.

TBH, at this point there isn't much you can do except buy another phone and move on.