imei number on an activation locked ipad

it does not have an IMEI

iPad Air 2

• Model number (on the back cover):
• A1566 on the iPad Air 2
• A1567 on the iPad Air 2 Wi-Fi + Cellular

Identify your iPad model - Apple Support

IMEI is a cellular thing only wifi cards and devices with only wifi does not have a IMEI

read more

https://en.wikipedia.org/wiki/International_Mobile_Equipment_Identity

IMEI has nothing to do with activation lock. Only person who put activation lock in ipad can remove it.