Taylor,
to your first question "a" : Yes we would call the navamsa signs by their rasih sign names, as we then map where that sign is in rashi and can see if the planet's navamsa falls in certain houses from the rashi lagna.
Ex: Virgo rising with Venus in Sagittarius but in Virgo navamsa = so venus now has it's navamsa in the 1st house or "lagnasma" .
B: Classics do speak of exaltation navamsa, or a planet being in it's "own" navamsa, so yes. Mooltrikona I guess is just the entire sign now (like venus in libra d9) but someone can correct on that one.
C : I don't see classics using ownership like a planet becoming "5th lord of navamsa" , instead if they do it's only in a more "modern" classic where they use navamsa tulya rasi / rasi tulya navamsa techniques, (overlaying charts... like placing the d9 lagna into the rasi and read the chart from that. or Rasi lagna into navamsa and read from there)
D : I see it similarly to how many read nakshatra.....where say if Moon is in Krittika, then some say it's in the nakshatra of sun - so then we see where sun is placed and say moon is giving some results of sun's position.
So example: Cancer rising with moon in Taurus but in Aquarius navamsa , we say moon has given it's navamsa to the 8th house, but moon is not suddenly also aspecting the 2nd house (from the
. since moon is not actually there, instead it's sitting in a navamsa/sign that being 8th from lagna; carries with it 8th house results (the sign) from the lagna.
Sort of like with nakshatra moon in krittika does not suddenly mean moon is also throwing an aspect from wherever sun is sitting, (or say sun is conjunct jupiter, it does not create a "moon+jupiter conjunction/gaja kesari" just because moon's nakshatra lord is placed over there)
Sorry that may have all seemed very confusing...I just woke up. ha
I believe varga "charts" started because it was an easy way to create a reference diagram to see what signs every planet's navamsa was in, and specifically to see where those signs fell from the lagna's navamsa sign.
Then astrologers could see which planets were 6/8/12 or kendra,etc from the sign of the lagna's navamsa (note: "navamsa of lagna, not "navamsa-lagna")
Also perhaps originally navamsa "charts" were drawn by using the Rashi lagna as the ascendant, that was astrologers could just see which houses from rasi that planets navamsa fell in (mostly to check any planets falling in 6/8/12 from rashi lagna).
Anyway we will see what other members respond, and prepare for the topic to go crazy again. Lol
And in other news still, people quoting PVR - which is fine - but please tell us why you don't use Pushya paksha ayanamsa then? Since PVR himself is so passionate about it being correct, I assume followers of his would try it out, no?
And Khoo saying we have a group of young people spearheading their own way of thinking that varga charts are not read as rashi.... but in my experience with 2 different very old (70-ish) indian astrologers in real life (neighbors guru and some other one my friend and I went too) they did not use any varga chart to predict, however did check my navamsa planet's sign strength only.
Just saying it's not a "young" thing only. And they said they used techniques from their family/parampara
sure they could be "Wrong" ,like how everyone : KNR , PVR, VPM , etc.. can be "Wrong" too.
*like PP ayanamsa