I read with profound interest your illuminating and instructive commentary to Bava Basra, Daf 91a. Accordingly, the daf found it necessary 'to give the name of Avrohom Avinu's mother (Amaslai bas-Karnevo), because the Torah (already) supplies us with the names of Yitzchok and Ya'akov's mothers, so we need to know that of Avrohom too.'
Moreover, the name of Dovid HaMelech's mother (Nitzeves bas-Adael) was also provided for. Again, according to your commentary: 'We need to know this because the (mothers') names of all the other (Judean) kings mentioned in Melachim are (also) mentioned.'
(a) I feel compelled to point out that unfortunately, that is not so, for as the case is, the name of Sha'ul HaMelech's mother is never mentioned anywhere in the Talmud, Midrash or Aggadah. Additionally, Sha'ul perplexingly remains the first and only king throughout the entire Tanach whose age upon throne ascension and age upon death also isn't mentioned whatsoever.
By comparison and contrast, the only other king whose age upon first becoming king and at death also isn't mentioned in Tanach is Shlomo. However, both Shlomo's age upon becoming king is amply provided for in the Aggadah (Seder Olam Rabbah 14), including his age upon death (Midrash HaGadol, B'reishis 3:26).
Furthermore, in another related difficulty, the name of Y'hoshua's mother also intriguingly remains unknown, although of course the mother's name of his predecessor, Moishe Rabbeinu (Yocheved bas-Levi) , is listed several times.
I must ask - was it also not intrinsically pertinent to equally providde the names of both Sha'ul and Y'hoshua's mothers, including both of their fathers' names and their corresponding tribal origins? After all, Y'hoshua was our first leader after Moishe Rabbeinu's death, and Shau'l was our very first king and Dovid's predecessor. Likewise, both tzoddikim were descended from Rochel Imenu, all the more reason additionally appropriate emphasis on their mothers' names and tribal origins should have been included in Bava Basra 91a and/or in other source citations.
Therefore, why wasn't any of this essential and consequential corresponding information pertaining to these two great, outstanding men not included in the daf, or in other commentaries? If such information is indeed extent, as is should be as an issue of integral consistency and preservation to complete our historical record, then what are the sources for them? To say the least, these are glaring omissions and oversights; therefore, such gaps must be accounted for and rectified, as is the demanding, continual purpose of Divrei Torah and corresponding commentaries.
(b) You also failed to specify that it is strictly the m'lachim from the Judean/Davidic dynasty whose mothers' names are mentioned. Notwithstanding, that same situation doesn't apply whatsoever to the Northern Kingdom, where none of their mothers' or even wives' names are mentioned, except for, of all people, both Achav's sister and wife, namely the wicked queens Asaliah and Izevel, whose fathers' names also happen to be mentioned alongside theirs. Compare that to Sha'ul, which at least lists the names of both his wife (Achinoam) and even his concubine (Ritzpah), including both of their fathers' names (Achima'atz, Ayah) as well.
Additionally, two prominent kings, Achav (from shevet Ephraim) and his immediate successor Yehu (from shevet M'nasheh), were relatively part of the longest, more successful dynasties in the Northern Kingdom, so by expansion and extension, more emphasis and attention should've been paid to their genealogical backgrounds, especially since offspring from both Achav and his father Omri eventually merged with and married into the Davidic dynasty.
(c) Lastly, the daf intrinsically implies that the mothers' names of other tzoddikim besides Avrohom Avinu and Dovid HaMelech were equally well-known by Chazal, but for some reason, simply never preserved in writing. Apparently, those three specific instances cited in the daf, namely Avrohom, Dovid and Shimshon, with the latter's sister's name (Nashyan) parenthetically being cited for extra measure and also as a specific point to refute the ongoing criticism of minim, were only provided for as an example that reflected the wealth of information that Chazal clearly possessed. Certainly, there are many Y'hudim who are interested and so have subsequently inquired throughout the ages about this information.
As such, have any commentaries to Bava Basra 91a similarly extrapolated the mothers' names/fathers' tribes of numerous other men in Tanach not explicitly mentioned, but also wanting? For example, just as the mothers' names of Shimshon (Tzlalponis/HaTzlelponi bas-Yachas, also cited in BaMidbar Rabbah 10:5) and Sh'muel (Chanah), sans the latter's father's name, are duly provided for, yet not those of two parallel manhigim here, notably Ehud ben-Gera and Eli HaKohen (both the latter's father and wife's names remain conspicuously absent). If not, then why haven't the poskim neither preserved nor provided those additional mothers' names/fathers' tribes in later commentaries, when it was clearly warranted for markedly greater elucidation and edification?
I would appreciate a personal reply regarding this matter, as I have already inquired about it for over the last three years, without ever receiving a satisfactory and comprehensive answer. Thank you for your help and time.
(a) As far as I can tell, except for the Davidic (Judean) kings, names of mothers and wives and such other "extra" information are not provided as a matter of course. They are only mentioned if they were part of the events the Torah is (or will be) describing - as is the case with Moshe's mother, Shaul's concubine, Achav's sister and wife, and Shmuel's mother. This may be why the Talmud wants to know the name of Shimshon's mother; she was a main character in his life's story, yet she remains unidentified. (The only other women with such important roles are the Shunamis, Tzarfasis, and Teko'is - but in that case the Navi at least tells us their city of origin.) If so, there is no reason to expect the Torah to name the mothers of Shaul, Yehoshua, Yehu, or Ehud ben Gera.
Thus, the bigger question is why the Torah does mention mothers and wives of Davidic kings. Perhaps it is to testify to the purity and holinesss of their lineage since Hash-m only rests His Presence upon those whose lineage is pure and untainted (see Kidushin 70b). The same applies to the Avos who fathered the nation upon which the Presence of Hash-m will always rest.
I hope this helps to make the omissions you mention less glaring.
(b) Your point that Rashbam is only referring to the Davidic dynasty is well taken. I addressed the other points above.
(c) I don't know if there were traditions regarding the mothers that were not discussed here or if only these were handed down. Traditions are not usually meant to simply satisfy the curiosity of wondering Jews. Every word of the Talmud has multiple levels of meaning.
I hope this helps point you in the right direction towards satisfying your three-year long quest.
Kollel Iyun Hadaf