You're kind of stuck here.

• Perl won't let you assign to the non-lvaluable thing you tried in your original example.
• You'll have a lot of trouble doing something like

  (@a, %h) = anything()
  [download]

  because @a will always get everything that is returned. (An artifact of the way perl handles nested list contexts.)
• So that leaves you with something like

  ($href, $aref) = (@{&foo})
  [download]

  which is basically what you came up with on your own.

Once you've got the references, you can dereference them one at a time, as you are doing, but good luck trying to assign (copy) them all to "real" arrays/hashes at once because of that second point above. Anyone who knows any better than I do care to comment?
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"I hate it when I think myself into a corner."
Matt Mitchell