After pondering the places that the words from root mim-ra-alif appear, I am sensing that something these verses have in common (not all but most) is that wherever im'ru-on or im'ru-ata are mentioned, it is usually to do with whether they have had children or not... which makes me think of capability to reproduce, and also makes me think of the women who are past child-bearing age. Some women mentioned are "ajuzun" (possibly either simply old age, weakened, powerless, incapable or confused) 51:25, 11:72, 26:171 and 37:135, all described as im'ra-atu) , and therefore could be at risk of starting to become forgetful, as well as possibly no longer fertile.
An old man is mentioned in 28:23 (I think that would be Moses' father in law) as an old man (a sheikh not an imrun)
4:176 mentions a im'ru-on that has no children. 19:28 Maryam was told her father (Imran) was not an im'ra-a sawin and her mother was not baghiyyan (possibly seeking to get pregnant?). Mary is the daughter of Imran (66:12) Imran's im'ra-atu is the mother of Mary but she was never unchaste (19:28) so it could be that she was infertile and was granted a daughter by the Will of Allah. In 3:35 she dedicated what was in her womb to Allah. Maryam went to be taken care of by Zakariya whose wa-im'ra-atī was sterile (3:40), and then they received Yahya.
I infer from 4:12 that a man can be a recipient of the whole inheritance if he has offspring who are no longer around to receive their share of it, and if he does not have offspring, then they are im'ra-atun. But in either case they may have brothers and sisters they can share the inheritance with.
4:128 gives me the impression that if there is a couple who do not have offspring and the im'ra-atun thinks her baʿlihā does not want to stay with her because of her inability to conceive, then there is no junāḥa for them to reconcile. Junaha could be inclination/reason (see the same word in 4:101 which would change the meaning of that verse - the famous shortening of the salat)
In 28:9 we see that Pharaoh's im'ra-atu wants to take Moses as her own son (maybe because she can't have children of her own) The same thing happens in 12:21
Another clue about the im'ra-ata is in 66:10 both im'ra-atu of Lot and Nuh are described as "taḥta ʿabdayni min ʿibādinā"
In 66:11 is another clue that a im'ra-atu is someone (here the Wife of Pharaoh) who is being oppressed or is helpless in some way
In 11:71 the wa-im'ra-atuhu reacted in that way possibly because it was a shock to be told she will have offspring after she thought she was infertile/no longer fertile.
19:5 ... my im'ra-atī is infertile ...
19:8 He said, "My Lord, how can I have a son when my im'ra-atī is infertile, and I have reached a very old age?"
51:29 His im'ra-atuhu then approached in amazement. She slapped upon her face, and said, "I am a ʿajūzun ʿaqīmun!"
In 28:23 two im'ra-atayni are mentioned and later on Moses marries one of them.
In 2:282 3 adjectives are used to describe what could possibly be the im'ra-atani safīhan, ḍaʿīfan or yastaṭīʿu anyumilla huwa which explains why one would need to be reminded if the other taḍilla, if the 2 wa-im'ra-atāni are old or senile or not in complete control of all their faculties
16:70; 16:70 God created you, then He will take you. Some of you will continue to the most miserable age so that he will not know anything after knowledge. God is Omniscient, Omnipotent.
22:5; 22:5 O people, if you are in doubt as to the resurrection, then We have created you from dirt, then from a seed, then from an embryo, then from a fetus developed and undeveloped so that We make it clear to you. We settle in the wombs what We wish to an appointed time, then We bring you out a child, then you reach your maturity, and of you are those who will pass away, and of you are those who are sent to an old age where he will not be able to learn any new knowledge after what he already has. You see the land still, but when We send down the water to it, it vibrates and grows, and it brings forth of every lovely pair.*