Given the strength of the mysterious enemy who invaded Konoha last night, the Third Hokage had no reason not to understand how difficult it would be to rescue Biwako Sarutobi under those circumstances.
In public and private terms, promoting Yuhara to jonin ahead of schedule was only a small reward. In the Third Hokage's view, Yuhara's current strength was absolutely enough to serve as a jonin.
As for why Kushina would directly speak up for Yuhara, there was even less need to explain it... At the most critical moment last night, Yuhara had been the only Konoha Ninja to appear before the couple. With that as the foundation, no one could stop her emotional inclination.
After the higher-ups finished their meeting and everyone had left, Kushina remained seated in the conference room. The place was dark and quiet, with only a sliver of sunlight filtering through the gaps between the crisscrossing curtains. In that environment, Kushina remained silent for a long time... Sorrow was difficult to share or divide with others. Only Kushina herself knew what she was feeling.
Sometimes, people who appeared strong had merely hidden their vulnerable side, because reality demanded that they be strong.
After a while, several other ninjas appeared before Kushina.
Shibi Aburame, Aoba Yamashiro, Shiranui Genma, Namiashi Raidō, and Iwashi Tatami. Except for Shibi, the rest were ninjas whom the Fourth Hokage had favored, promoted, and appointed. Now, to put it nicely, Kushina had inherited the Fourth Hokage's political legacy. To put it less nicely, these young ninjas would certainly be marginalized from this point onward.
Objectively speaking, this was not deliberate exclusion. It was simply something that would happen naturally. After the Third Hokage regained power, he would certainly use the ninjas he had always found most reliable. Surely no one could expect