1. Partial "original" from Cochlaeus.
2. English translation of Luther, apparently from the German original.
3. Armstrong has the German original of Luther as produced in his "works," which we expect will simply reveal that the English translation is accurate.
4. We also have a practically illegible (to me) photograph of a single page from a manuscript copy of the work in question, in Luther's hand.
5. I don't think anyone has bothered to obtain a copy of the original German work pre-compilation into Luther's works.
6. Apparently, no one has been able to get a copy of the original "official" translation of Luther.
At this point there are several possible outcomes.
1. If the English ends up essentially matching the German and "official Latin" we can simply agree with Whitaker that the "quotation" made by Cochlaeus is a spurious gloss, and Catholic apologists should have heeded Whitaker's warning.
2. If the "official Latin" ends up matching Cochlaeus' Latin, it will be a bit surprising, but we will have to acknowledge that Whitaker may well have been wrong.
3. It seems fairly apparent that the single line of German that Armstrong has produced does not correspond to Cochlaeus' Latin, but does correspond to the English translation (cf. the German back-translation from the Latin previously provided). However, if the "German Scholars" (apparently including Steve Ray's relative and one other person) conclude otherwise, we will have to figure out why they do so.
I suspect that we will end up with number (1), which will demonstrate that James Swan's intuition was right all along.
1. So far, I think it is resaonable to conclude that none of the Catholic apologists except Cochlaeus ever read the Latin sentence that Cochlaeus reported in any work by Luther. As such, if no more evidence appears, we can simply dismiss the alleged "quotation" as a spurious gloss loosely based on a sentence with a different meaning, and handed down as - in effect- an "urban legend" via reliance on secondary sources by Catholic apologists.
2. Also, I think it is reasonable to conclude that there is no other Luther work from which Cochlaeus might have gleaned the spurious gloss than the one that has been identified.
3. Finally, I think it is reasonable to conclude that Leibniz (putatively a Lutheran, not a Catholic) simply borrowed from Bellarmine.
These preliminary conclusions would be rather different if the "official Latin" turned out to match Cochlaeus' gloss - so we are, I suppose, still waiting to see what will be pulled from the hat.
Incidentally, while I probably have missed some things along the way, I think this quotation by Ranolder of Cochaelus' gloss has been omited from Armstrong's list (link). Of course, unsurprisingly, his wording is roughly the same as those who went before him, with no additional context provided.