iMessage and Facetime not working
Following on from previous answer (I can't seem to comment) it hooks to whichever one is available. For an iPad that has had a SIM card in it, it'll hook to your phone number. If you have the SIM, re-insert it and ensure it's all working, then head to iMessage and Facetime settings and add the email address to both of them. After that, you should be able to take the SIM back out and it continue functioning.