The challenge is to have the Radical Republicans not only come up with the idea to deport (as opposed to other forms of punishment) Ex-Confederate soldiers and collaborators, but have the policy successfully be enacted. Where could they've realistically be sent to, and what sort've effects might this have had on post-War America and the world at large?
Honestly, to put this simply, deporting *all* ex-rebels almost certainly wouldn't happen even under the most radical Republican administration; that said, though, that doesn't mean that ex-Confederates would necessarily have free reign-it's not at all hard to see, for example, some states outside the South, perhaps especially out West, putting heavy restrictions on residency of the former Rebels, outside those who can prove their loyalty to the restored Union(though in most of these scenarios, I'd wager that those who
could would probably be able to settle down like anyone else coming there.)
(On the other hand, since this topic has been breached.....I realize this is a bit off topic, but no, it is not that likely,
even IOTL, that you would have had such enthusiasm for deporting the freedmen-yes, even in
our universe, there were many abolitionists and even a fair number of non-radical Republicans who actually
had intended for the freedmen to have equal legal rights, prejudices of the era aside; had this not been the case, we almost certainly wouldn't have had the 14th and 15th Amendments and maybe not even the 13th. Yes, there
could be a few plausible scenarios to do this, but far easier discussed than actually written.)