post: if Guion sends records of his twentieth century interviews with Everard to a Patrol base in the far past, then those records will be at least accessible, whether or not they are also helpful, to an Unattached agent trying to counteract a historical change in a subsequent timeline. I am tempted to leave the matter there but, of course, the story always gets more complicated.
Let us suppose that the Unattached agent is Komozino and that the subsequent timeline is the alpha timeline of The Shield Of Time. We know that the alpha timeline is followed first by the beta timeline, then by the restored Danellian timeline. Thus, along the second temporal dimension, there is a chronlogical sequence of four timelines:
(i) the timeline inhabited by the Danellians and defended by the Patrol;
(ii) the alpha timeline;
(iii) the beta timeline;
(iv) the restored Danellian timeline.
In (i), Guion acts as described above, then returns to his home milieu.
In (ii) and (iii), neither the Danellians nor Guion exist.
In (iv), Guion acts as in (i). He might then be informed of the deleted alpha and beta timelines but does he need to know? If the purpose is to restore (i) with as few alterations as possible, then maybe he should not be told?