Despite being an android, the mother of the Hargreeves is a sentient being and could have chosen another group of heroes, other than the The Umbrella Academy of the 36 that Reginald left behind, doing what their creator did, but better.
Grace from The Umbrella Academy may have harbored similar misgivings after breaking up with Reginald. With her scientific mind set, it stands to reason that Grace will continue to investigate Reginald’s affairs after the events of The Umbrella Academy season 2.
Through her spying on The Umbrella Academy, an older Grace could have followed Reginald during the 1989 world adoption spree, picking up the babies he rejected and raising them in his own superhero team.
This secret group would be trained to counter her ex’s Sparrow Academy should the occasion arise, and could also include some very familiar faces. It is still unclear what happened to the original children of The Umbrella Academy in the alternate future of 2019.
Having been rejected by Reginald, did Diego and the others end up in Grace’s care? This would create a fascinating thematic parallel between the two versions of Grace from The Umbrella Academy.
In The Umbrella Academy’s original timeline, Grace the robot was programmed to take care of the Hargreeves brothers, but even when the story changed and Grace left Reginald, she still became a mother figure to the same children, this time as human.
With Grace’s third team in season 3 of The Umbrella Academy, the Hargreeves brothers got a glimpse of what their lives might have been like with a caring father, rather than an emotionless alien who sees them only as weapons.
The idealistic version of Grace from The Umbrella Academy also creates moral conflict for the Hargreeves brothers. If Five and the gang fix the timeline to eliminate the existence of Sparrow Academy, they will deny their alternate selves a happy upbringing with Grace.