...

Unnecessarily complex card to consider for future design space.

"all permanents that share a name with it"?

Nope. Only the cards and tokens representing that single particular permanent. See mutate/meld.

A less unnecessary complex version of this would be:

> "Return target creature to its owner's hand, then its controller creates a token that's a copy of that creature."

with only minor functional differences (e. g. whether spells/abilities that targeted the original still target the copy).

If you Unsummon a mutated or melded permanent, all of the components go back to their owner's hand anyway. This is functionally identical to "return target nontoken creature to its owner's hand. Its controller creates a token that's a copy of it"

Eta: I didn't read the second half of your comment

As the first comment points out this is complex beyond necessity. It's just a small reminder that it is possible if I ever need this design space for something worthwhile.

Maybe just turning a single card of a merged permanent into a token is the solution to a puzzle at some point?