If Tarkin is still alive.

It was around pre-yavin 4 that the interdictor was used to hunt an Mof traitor if I aint mistaken.

Build by moff tarkin because he in the clone wars had made the first designs of the ship.

Upon these designs an interdictor can be refined and build.

Also about my emperor question. Normaly he should be able to be reborn because he had the power of essence transfer.

Wait Tarkin serves your faction?

Also will we see thrawn leading the chiss? What about the unkown reaches will we get a map for that