If you are using Gmail like abcdef@gmail.com for 1st phone, then you can use abcdef+1@gmail.com for your 2nd line, all emails will go to same abcdef@gmail.com account.
Yes, you can self refer yourself. However, you will need to activate the second line under a separate account/different email address. You can use the same name and credit card for autopay, but need different email address to access 2nd line.
