Problems with Cases -- Ideas?

I've been wondering just how much grammatical terminology
a 17th century monk like Conrad Vogelin would have had at
his disposal to describe Hairo.

Would he know the terms absolutive and ergative at that
time?  Would he invent other names, or maybe even map Hairo
grammar onto Latin case names despite the ergativity?  Are
there old German names for absolutive and ergative, or would
he have used the Latin names?

Also, would he be familiar with construct cases?  I'm
currently intending to give Hairo an implied "and", i.e. two
juxtaposed nouns |A B| would be parsed as "A and B" rather
than a noun phrase with one noun describing the other.
Obviously, I would then need a case to make one noun a
modifier of the other.  I'm thinking of using my current
genitive for that (a construct case misnomed by Vogelin,
maybe also with residual genitive functions)...

   |brand mwîr| {man father} "the man and the father"
   |brande mwîr| {man:GEN father} "the man's father"
   |mwîre brand| {father:GEN man} "the man, who is a father"
      (apposition, as in Latin VIR PATER?)
   |brande conrad| {man:GEN Conrad} "the man Conrad; Conrad,
      who is a man"

Would that be too confusing in cases like {son:GEN father},
where both construct "the father, who is a son" and genitive
meaning "the son's father" would make sense?  Should the
genitive meaning be taken over exclusively by a
postposition?

   |leom mwîr| {son father} "the son and the father"
   |leome mwîr| {son:GEN father} "the father, being a son"
   |leom us mwîr| {son POS father} "the son's father"

Or, what I'd like even better but tastes a bit too Germanic:

   |leom ane mwîr| {son his father} "the son's father"

But then, how to say "the son and his father"?  Argh!  Maybe
a "strong and" like Latin ATQUE should be available in the
form of a conjunction (or a postjunction?):

   |leom gu ane mwîr| {son and_also his father} "the son
       and his father"
   |leom ane mwîr gu| {son his father too} "the son and his
       father"


I'm not quite seeing through.  Feedback welcome!



-- Christian Thalmann