Assuming that you amended for PMI only and not other income or deductions -
(1) Form 1040X - this definitely gets sent
(2) Form 1040 (new version) - ok, this one you are likely going to see differing answers out there and both are really correct. Some will say you don't need to send the new Form 1040 because Form 1040X replaces that form and you are sending the Form 1040X. Some will say you do need to send it because the 1040X instructions tell you to send any form that has changed and this one will have changed. Many people never send it and are never asked for it, but it really doesn't hurt to send the new Form 1040 just to be thorough and avoid any even small possibility you may have to deal with the IRS again if they were to ask for it.
(3) Form 1098 - this is an informational form, so a copy of this does not need to be sent (but again, if you want to send a copy, it doesn't hurt)
(4) Schedule A (new) - since you have changed your itemized deductions, you will need to include a copy of the new Schedule A showing this addition of PMI
