Thief Has My Passcode

My iPhone 6s was stolen. After a couple of weeks, Find My Phone tracked it, and I got email alerts that my apple ID info has been changed. They gained access using my passcode, deactivated lost mode, and began messing with my account.

I have other devices on the account, and even though I had already reported to the mobile carrier and deactivated that sim, I worry that my 2-step verification codes were still sent to that stolen device (as it is sent to all devices) as I attempted to change my apple account password to stop their access. Because of this, I also removed the device from my list.

Now, I wish to erase the device, it is showing in Find My Phone that the erase is pending, but will it be able to if I already removed it from my list of devices in my apple account?