III. More differences abound when looking at the birds’ return to Noach (or lack thereof):

It’s a fairly heavy passuk, if you really look at it. The dove returns not only to the Ark for shelter, but TO Noach himself.

V. Additionally, the Torah implements some word play in writing that the dove did not find “manoach” (rest) on her mission – she could not find a restful perch outside the Ark, away from Noach, so she returns to find manoach with Noach.

VI. The closeness is perhaps most apparent upon the dove’s second return. (8:11)

VII. Also, the olive branch is not only a sign of the existence of foliage (and peace), but also materials a bird would use to build a nest – AKA a home.

VIII. Staying with passuk 8:11, the Torah says:

IX. Finally, for Dispatch #3, the Torah only says that the dove was sent (i.e. not “from Noach”, like in Dispatch #1 in 8:8), and the dove does not return – further diminishment of closeness as noted at the end of Point VII.

The most common admonishment of Noach in Chazal is that, unlike Avraham, Noach uttered not a single word of protest nor attempt to save his fellow man when Hashem informed him of impending destruction.
Noach needed to learn the lesson of thinking about and caring for others (kavod ha’brios and ahavas ha’brios), and he needed to do so on his own (note that Hashem does not instruct Noach to send out the raven or the dove; it is Noach’s own initiative). He cares for the dove, and the dove cares for him.

The evening (as noted above – the time of day when the dove climactically returns with the olive branch) is also a transitionary period. It transitions day into night; yesterday into today (per our lunar calendar). In the evening you transition from being a spouse away from your husband/wife during the day, to being reunited spouses in the evening (unless you’re a doctor, banker, lawyer, accountant during busy season, etc., in which case it’s more likely you reunite in the early morning hours). Perhaps Noach begins to make the transition into a more caring person. He is eager to take the olive branch – a sign of the earth healing – and imagine an improved world, replacing the “chamas” that had filled the world prior to the flood (6:11), with chessed.

As for the 7 day wait, and the dove’s lack of return, of course in a real (human) marriage, we hope that a spouse is not sent away immediately after Sheva Brachos never to return again, as in Dispatch #3. That would be rather sad.

Noach obviously was not going to carry on a romantic relationship with the dove. But having developed the characteristics of care for the dove during his time in the Ark, he no longer needed the dove, but not in a cold way. The relationship with the dove diminishes, because Noach begins to internalize the lessons of compassion and closeness. Noach is now ready to step out into the new world.
Infused with ahava and chessed, Noach is ready to properly return to his wife (with whom he was not allowed to have relations with while in the Ark) and his family, and shoulder the responsibility of rebuilding and caring for humanity.