>>During its history, the acadamy was not only a meeting place of the academic elite. It also provided a haven for many anonymous scientists to pursue their work.<<---Geisteswissenschaften: arts, humanities (Oxford-Duden). It follows that Geisteswissenschafler are academics in the arts and humanities.

Hope this helps

1. Repr"asentationsort is a place for displaying or presenting or showing off. I used to work in a research institution which was called the "flagship" of the larger organization it was part of. You could also tone down the showy part a bit and call it a Center of Excellence. "This academy has been, during its history, not only a showcase of the scientific elite, but also the workplace of other scientists who have remained largely unknown." The word other is implied and avoids confusion in English. It also helps your prose cadence.
2.Geisteswissenschaftler are in the humanities, as distinct from science.

This institution was historically not
only a prestigeous/impressive/representative place (or: a place representative) for the academic elite, but also a place
of research for the scientists who
largely remained anonymous.

Geisteswissenschaften wird vorwiegend mit "humanities" uebersetzt (liberal
arts bedeutet dasselbe, aber ich wuerde
es nicht benuetzen). Historically speaking were the humanities for a long
time the only subjects to study. They
encompassed Theology, Philosophy (natural science was part of it). Only
in the 18th century and on into our times more specialized fields of study were created. But even today one
speaks of i.e. a B.A. (B. of Arts)which
means the person has studied subjects in
humanities or liberal arts.

I don't have anything to add in terms of the major part of your inquiry, but keep in mind that "scholar" might also work for "Geisteswissenschaftler." By definition, which is to say according to my Websters, a scholar is a learned person or specialist in a particular field, "especially in the humanities."