A lot of the mid-'80s novels drew on Ford's Klingons and Duane's Rihannsu; they pretty much came to be regarded as the definitive interpretations. Perhaps the one exception is Pawns and Symbols, which came out after The Final Reflection but portrayed the Klingons in an incompatible way.
As for what was included in the internovel continuity that gradually evolved at the time, I find that the simplest way to get a handle on it is to check the acknowledgments of Time for Yesterday by A. C. Crispin, the one book that drew the most heavily on earlier novelists' work, and is thus something of the linchpin of that continuity. In addition to being a sequel to Crispin's Yesterday's Son, it references the books of Diane Duane, Brad Ferguson, John M. Ford, Jean Lorrah, Vonda N. McIntyre, and Howard Weinstein. The Ingrit Tomson references tie J. M. Dillard's series of books into the sequence, and Dillard's The Lost Years references Diane Carey's Dreadnought! and Battlestations! And Uhura's Song by Janet Kagan references a character from McIntyre's The Entropy Effect.
Let's see, going through Voyages of the Imagination, I'd list the following as definite parts of the 1980s Pocket novel continuity, keeping in mind that it's a fairly loose continuity:
The Entropy Effect
Yesterday's Son
The Wounded Sky
The Final Reflection
My Enemy, My Ally
The Vulcan Academy Murders
Uhura's Song
Shadow Lord (references McIntyre's Sulu backstory)
Dwellers in the Crucible
Mindshadow
Crisis on Centaurus
Dreadnought!
Demons
Battlestations!
Deep Domain
The Romulan Way
How Much for Just the Planet?
Bloodthirst
The IDIC Epidemic
Time for Yesterday
Rules of Engagement
Doctor's Orders
Strangers from the Sky
Spock's World
The Lost Years and its sequels
The list is mainly in publication order, with hardcovers last, for my convenience. The in-story chronological order would be very different.
There are others I'm not so sure of. Maybe Enterprise: The First Adventure or Final Frontier could go in there too, but I don't recall any cross-references offhand.