Morrigan denied, Blight defeated, and Alistair still your friend/lover/consort (as you decided earlier.)
1. Execute Loghain at the conclusion of the Landsmeet.
2. When time to choose your final crew, leave Alistair to guard the Gates at Denerim, or the big lug will rush to "do the deed" anyway.
3. Make a (Named) Saved at some point inside Ft. Drakkon. (I do this right just outside the roof-top door that leads to the "Last Battle", but really, anytime after entering is fine.)
4. Exit and re-start DA:O with the command console option.
5. When you're ready, start the console and use:
runscript zz_addparty Loghain
to add Anora's father (now evidently resurrected and Joined) to your group.
NOTE: Since you have never had him on your team before, you will NOT be able to adjust his tactics to ensure he heals himself when necessary. And since you won't be able to "tell" him to use potions either, be sure you have a healer with you and that they focus on him. The whole point is to have both of you around at the end.
6. At the appropriate point he requests being allowed to strike the killing blow. A request which you are more than happy to grant.
And there you go! There is one "Post Coronation" bit of dialogue that's off. Anora asks how her father met his end, even though she witnessed the Landsmeet. (Alistar isn't sure how/why you survived either, but in that case one of the offered responses works very well for the situation.)