Gst on purchase of machine from unregd. dealer

Scenario: A Registered Person is buying a machine (worth 10 Lakhs) from an Unregd. Person situated in Location A in India, This machine has to be transported to another location B in India and from there this machine would be exported (as a Sale) out of India.

Question: In the above scenario,

1.Should the Regd. Person raise a self invoice under RCM for the purchase of Machinery

2.For transportation within India how should the eWay bill be raised.

3. For the RCM, if Paid, can the credit be taken in the registered person's account and then can a refund be claimed in full, as this person is involved in Exports only.

Thanks!