Other folks will address Felix Delbrueck's specific questions on the Bach
cello Suites recordings, but a couple of comments on the overall question.

Not only are there variations in interpretations among various HIP artists,
some of those artists (and the folks who are partisans of one of them or
another) aren't above making pointed disagreements as to recording details,
or overall performance philosophies.

Just like folks in the various non-HIP circles who argue over and over why
Gottfried von Furtgesanger's Beethoven/Brahms/Schumann/Mahler/Bruckner
cycle is better than Massimo della Fettucini's.  Or vice versa.

Perhaps one difference is that what constitutes "HIP" has changed over the
years, as more and more source material is discovered, more scholarship has
taken place, and more about the instruments and what they can do is found
out.  Certainly it has made a difference in the proficiency of HIP playing;
whether it has "improved" the interpretations is up to the individual
listener's taste.

But overall, it shouldn't be surprising that HIP artists too have their
artistic and interpretative differences, idiosyncrasies and such.  Or is
it?

Bill H.