My point isn't that the reference framework was a Tropical Zodiac - it wasn't. Neither was it 'only' a Sidereal framework I'm aware that there's an argument that the Babylonians were aware of precession over a thousand years before Hipparchus but even if that were true (and it may well be) we are still dealing with situation in which the March equinox occured in Aries. When the equal sign zodiac was developed the March equinox was in the first 10 degrees of Aries. At that time no one distinguished between sidereal and tropical, as Dave says. It's also very probable that it was actually believed that the March equinox was fixed in Aries for all time (both past, present and future). In such a situation can we really insist that actions are in a sidereal, rather than an equinoctial framework, when the people concerned had no conception of a distinction or difference?
Of course marker stars would be used for calendar purposes, but the calendar was largely determined by equinoxes or solstices. For many calendars (including the Babylonian) that link with the equinox or solstice is still the vital thing, they haven't shifted the calendar to keep in contact with certain star positions.
Yes, Dave is right to say that the exaltations were almost certainly established pre-Tropical Zodiac (in the sense of a Zodiac measured from the Equinox) but the were established in a Zodiac which was both sidereal and seasonal it was not just sidereal 'only'. Of these two components of the conjoined zodiacs (which we can see they were with hindsight) which was Astrologically the most important? I can't answer that, nor can Dave - history suggests Tropical in the West and Vedic in India, so there's no definitive answer to that one.
Dave is also right, in a previous post in this thread, to point out that the exaltations were originally linked to specific degrees, I don't know of any definitive explanation of the origin of these degrees, either by Tropical or Sidereally based Astroogers. I think it's a question of 'Watch this space' and for people like Dave and me, that's what makes Astrology so enthralling.