Add an iPhone number to other iOS devices to receive iMessages/Facetime calls via the phone number?

Solution 1:

No,

iMessage and FaceTime are linked to your Apple ID so you will need to add your Apple ID to the device, not your phone number.

If you send a message from the iPad it will use the Apple ID, so someone can reply to your email address, if they send a message to your phone number it will only go to your phone.