There is no reason the options you've outlined shouldn't work in the tapestry. Just make sure you're selecting that your warden kills the archdemon (others have made that mistake and wondered why it made the dark ritual be undone).
I just made a tapestry with a romanced Alistair who had a baby with Morrigan and stayed with the wardens & the warden, Anora as the sole ruler and a living warden, so I don't know why it's not letting you do the same.
Lock your decisions as you make them, see if that helps? If it changes things, go back and change them back.
