Technically, ETP wasn't discontinued since it still exists under the ET umbrella, and must still be entered as a standalone K-1 in TT (since ET must be broken out into all there sub-entities). So assuming the ETP FEIN has't changed, you can enter ETP "normally" by just adding the values on the two K-1s.
If the FEIN changed, then you'd only check off "This partnership ended" and "Disposition was not via a sale". This 2nd one is important, because it keeps the passive losses suspended. This answer has a little more info on that: https://ttlc.intuit.com/questions/4726806-how-to-merge-passive-losses-in-mlp-merger
As for the basis transfer, that is for your records and doesn't need to be entered into TT.
