IPhone – If the iphone gets stolen, if i wipe all the information from the iphone from the icloud account it can be usable

Under Settings / iCloud you'll see a big red button labeled as Delete Account. Contrary to what it appears, it won't actually delete the account, nor your Apple ID, it will only delete the iCloud's content from your device.

So, to change the device's iCloud account just delete the current one and then log in appropriately.

As soon as the device connects to the internet, Apple's servers will send the erase message to the phone. I have seen this happen three weeks after the message was sent and the effect was nearly immediate.

I don't know of any way to recall the erase message once you've sent it, and you should receive an email if the device ever registers and the erase message is sent.

All the things you did after the erase request are moot since if the phone never checks in, you can't really stop the erase and if it does ever check in, it will get erased and self remove from your list of devices.

You might open a support ticket with Apple to be sure the email will send if you erase the device (I haven't actually tested that sequence), but common sense says you might expect the email if the erase ever gets issued.