Ok alternate idea- what if Bruce is the one who gets de-aged? For humors sake Alfred could be out of town for whatever reason, leaving the batkids to deal with the weirdness that is smol Bruce. Like 5 year old smol.
this is great, because i’ve always thought bruce was a weird lil kiddo who did weird lil things, and alfred was always running after him. what are you doing tearing up the garden, master bruce? saving the bees, you say? and like bruce was a master of the sneak from like 3, he could just duck away while the grownups are yelling and climb into the air vents. why the air vents? it looked interesting. very curious, the tiny batman. always running off to explore. what are rules
so like, imagine the kids all getting into an argument because you can’t put them in a room together, and suddenly bruce is gone, and it’s a total manhunt. in the span of six hours, bruce somehow finds his way to metropolis, and tells superman that he looks like a popsicle. he’s a strangely clingy little kid, too, so when dick comes to pick him up bruce just wraps around his leg. it’s slow, and sneaky, so you don’t notice, and it’s made alfred trip hundreds of times. bruce is amazed when dick just keeps walking and declares him the Favorite