Photo credit: National Trust Images
The etching by Johannes Meyssens shows a very similar looking sitter. A work in the Lviv Art Gallery in Ukraine suggests this too could be a portrait of the same sitter. Finally, anther portrait, which is in a private collection, looks to be again the same sitter, and is even closer to this portrait.
Links to the other images.
This piece https://bit.ly/2RAButb by Svitlana Stets, a curator/researcher at the Lviv National Art Gallery, says that their 'Rubens' work had by 2012 already been re-attributed to van Dyck and also identified as being van der Ee. I'm not wholly convinced that it is the original of the Myssens print, but it may be. The third one you mention "in a private collection" is I think just a rather poor copy of the Lviv painting (or another version of it) - is that the date '1846' on the right?
I can't, though, see our (NT/Cobbe Collection) sitter being the same man at all. A wise and experienced head observed here during a long and inconclusive C17th portrait thread** a year or so ago, that there is seldom much point in a "looks-like" approach to portraiture without documentation or other supporting evidence - and that becomes truer the further back in time you go. I don't think the faces of the two men look enough alike to make a convincing case; but that is just my subjective visual opinion, and Peter will doubtless disagree.
However, it is sometimes possible for a clear and simple physical detail to rule someone out: surely our sitter's *very* red hair (and beard) means he cannot possibly be the dark-brown-haired man in the Lviv portrait?
**https://bit.ly/2RAButb . I suspect the memory of that exhausting marathon may be restraining people's interest in this thread - it certainly did mine!
I tend to think this is not autograph van Dyck, at least not entirely, and possibly not at all. I do not have the Yale van Dyck catalogue at hand, so can someone who does tell us what it says about this piece?