Uchiha Hikari did not tell Minato Namikaze that the Masked Man calling himself Madara was actually Obito.
Because there was no point.
After turning dark, Obito was basically no different from a stranger to Minato Namikaze. His personality, abilities, goals... everything was completely different. Even his intelligence had improved a little; otherwise, he would not have gone unrecognized on the night of the Nine-Tails attack.
And Kamui, even among Mangekyo Eye Techniques, was one of the most broken abilities.
—Based on the original plot, the "Kamui Dimension" seemed to possess a certain degree of spatial teleportation ability. In other words, the coordinates for entering and exiting did not have to be the same. Obito had probably used this ability to pass through Konoha's barrier and infiltrate the village. If he truly wanted to hide, finding him would be no easier than finding Muzan Kibutsuji.
Unless they dug out Kakashi's left eye, implanted it into an Uchiha, and tried to develop the Kamui Eye Technique.
Or Minato Namikaze could personally travel over and use the Flying Thunder God formula he had left on Obito back then.
Uchiha Hikari had brought up the latter idea in the chat group once.
But...
Forever with Sis: ...My "travel" function is indeed usable, but there is a warning about unknown risks. If I travel recklessly, unforeseeable dangers may arise, so unless it is necessary, it would be better to remain cautious.
Nameless: All right.
Unknown risks... Did that mean that a soul without a physical body to rely on might be unable to exist steadily in the normal world?
Or might something go wrong when returning from the real world to the Death God's belly, such as alerting the Death God to something?
Uchiha Hikari had never died, so she did not know what it