Pretty sure the correct answer is what these reasons starts, not that the reasons exist. You might as well have answered with "Because."
-Infinite Tsukuyomi was all but certain
-Kaguya's return was a high possibility
-Madara was unstoppable without his intervention
-Sasuke (indra) deserved a second chance
-Naruto needed a final push and some final advice on how to deal with Sasuke
And frankly, Hagoromo probably wanted to meet the child of prophecy, and confirm his existence.
im pretty sure madara awakening the rinnegan warrants a talking to lol
That was the duty of Hamura's line, not Hagoromo's.
Besides, Hagoromo had no reason to believe Madara would succeed any more than his predecessors did, especially after he died. Remember that Hagoromo had no idea BZ was alive and manipulating the outcome.