Generally, only water soluble flavorings are recommended for vaping. Oils are bad for the lungs, as they are not expelled well, and may be associated with an increased risk of developing certain kinds of pneumonia.
But that's really all I know--and I know nothing about hemp oil, sorry. I guess a tiny amount mixed in with your PG/VG base would be OK, but why take unnecessary risks?
I don't know anything about the X6 batteries--but there are some old threads here discussing them. I suggest to run a ECF Google search:
http://www.e-cigarette-forum.com/fo...-voltage-1300mah-ego-battery.html#post9283883
CE4? I don't care for CE4s.

Sorry, I don't like top coils and the coils are not replaceable--pretty old technology. I suggest you get a simple Kanger clearomizer like TS3, eVod, ProTank mini or Aerotank mini.
Good luck.