Hello Ghingo,
To start us out, we'd like to offer a couple of support articles that can help with this situation: If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support and Use the Find My app to locate a missing device or item - Apple Support.
In addition, this section of the above listed article may help: "When you erase your device, all of your information (including credit, debit, or prepaid cards for Apple Pay) is deleted from the device. If you erase a device that had iOS 15, iPadOS 15, or later installed, you can use Find My to locate the device or play a sound on it. Otherwise, you won't be able to locate or play a sound on your device after you erase it. You might still be able to locate your Mac or Apple Watch if it's near a previously-used Wi-Fi network."
As to your specific questions:
- There is not a way to confirm that the phone was erased, but if the commands were accepted (and you do not get an error message, then the process was successful.
- Find My will show the location of the iPhone as of the last time it was on and connected to a network. If the location changes and it is again turned on and connected to a network, the location shown in Find My will update.
- Step 7 in this article (If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support), it explains the removal process. This would be done once you are certain the phone will not be found and used again, and after your claim has been approved (If you have AppleCare+ with Theft and Loss).
- The articles above cover what you need to know and do pretty well, but if you think there is any possibility that someone may have gained access to your Apple ID, this is a great article to review to protect yourself and your data: If you think your Apple ID has been compromised - Apple Support.
We hope this helps. Let us know if we can assist with anything else at all. Take care.