iPhone asking for icloud login after being restored after icloud has been removed
Standard procedure before you sell or give away your old iPhone/iPad etc
Don't set the phone up for the new user, they must do it themselves.
If you still have your iOS device
Before you sell or give away your device, you should remove your personal information.
You shouldn't manually delete your contacts, calendars, reminders, documents, photo streams, or any other iCloud data while you're signed in to your iCloud account. This would delete your content from the iCloud servers and any of your devices signed in to iCloud.

Back up your device.
Tap Settings &gt; iCloud. Scroll down and tap Sign Out. In iOS 7 or earlier, tap Delete Account.
Tap Sign Out again, then tap Delete from My iPhone and enter your password.
Go back to Settings and tap General &gt; Reset &gt; Erase All Content and Settings*. In iOS 7 or later with Find My iPhone turned on, you'll need your Apple ID and password.
If asked for your device passcode or Restrictions passcode, enter it. Then, tap Erase [device].
Contact your carrier for guidance on transferring service to a new owner. If you aren't using a SIM card with your device, you can contact them to get help transferring service to the new owner.

If you no longer have your iOS device
If the steps above weren't completed and you no longer have your device, follow these steps:

Ask the new owner to erase all content and settings as described above.
If you're using iCloud and Find My iPhone on the device, sign in to icloud.com/find, select the device, and click Erase. After the device has been erased, click Remove from Account.
If you're unable to follow either of the above steps, change your Apple ID password. This won't remove personal information that's stored on your old device, but it will prevent the new owner from deleting your information from iCloud.
If you're switching to a non-Apple phone, deregister iMessage.
If you're using Apple Pay, you can remove your credit or debit cards at iCloud.com: Choose Settings to see which devices are using Apple Pay, then click the device. Next to Apple Pay, click Remove.

Source : https://support.apple.com/en-us/HT201351