It does not merit a verification of the author, when you hold their content encaged somewhere they did not approve yet. You say it's to increase registrations on Fediverse and for the brighter future, but please remember to deal with this ethically. Creator deserves to know first that your mirror (or whatever ends up being) intends to seek engagement with their piece.
Linking to original, as we both proposed, is an aftermath. Top three factors also need to be addressed if you claim fair use.
As an alternative, asking for consent and delaying repost is not a rocket science.
TINLA: factors for fair use don't seem to align, though.
Such use does not characterize commentary, parody, etc. and is not transformative.
Post may prove to be substantial on its own, especially if it's an art piece.
Most of the work (individual post) or crucial parts being used.
Since there is most likely no thorough link to the author's website or profile, they lose the audience - nobody will go to look up the same post twice, not through Google and Google Images, especially.
About that last point: solvable by manually gathering authors' links or making a hyperlink to respective Reddit profiles.
The argument can be made that bots measuring the content are no better than some random dude on the Internet reposting shit they like. Situation becomes worse when that same "bot" doesn't credit the author proper.
It does not merit a verification of the author, when you hold their content encaged somewhere they did not approve yet. You say it's to increase registrations on Fediverse and for the brighter future, but please remember to deal with this ethically. Creator deserves to know first that your mirror (or whatever ends up being) intends to seek engagement with their piece.
Linking to original, as we both proposed, is an aftermath. Top three factors also need to be addressed if you claim fair use.
As an alternative, asking for consent and delaying repost is not a rocket science.