I don't think it's ever been established exactly what the orbit dynamics are in regards to which suns are up at which times. I would assume there is
some point where both are in the sky at once. But mostly it's just that the normal nighttime hours, are not dark for these 40 days, due to this second sun. It gets
cumulatively hot, for lack of a cooldown period. Figure four hours midday, where it is dual-sun hot.
Etzos has a long history of hostility with Rhakros, and has invaded before, so it stands to reason that the army has taken precautions, including bringing light, quick-assembly pavilion tents for quick shade and lots and lots...and lots....of water. On that subject, there is no shortage of water, and yes, there is danger in drinking from the fountain, as well as the city channels and irrigation systems. But the trip in brings every group past many sources of water, which will need nothing more than simple boiling and/or distilling to be purified, even the swamp water.
There is the Enan'uh Lake and River to the south. There are all that river's headwaters and streams coming down from the Dordain Mountains to the west. There are the swamp and many connecting streams in the Jungle. Really, only the group coming from the north does not have a lore-stated source. But again, Etzos has done this before; they would be prepared. And with the bulk of the army being ghosts, there will not need to be so much of it as usual.
I'm already figuring some extra Endurance points for everyone just for
being in the jungle in Saun, but I am not
requiring details of how you all avoid heatstroke and dehydration. Still, showing some effort in this regard could win you some favor.
But it can be assumed that there are non-combatant camp followers, medics, engineers and such whose duties are to see to such things.
yes, Curmantain stone is used in all building construction, but much of the wall is earth and wood with only some stone. I'm honestly not finding the bit where it says this stone is green, but that is hardly any big deal. Sure, let's say that Rhakros is largely green in color
. But the water in the channels is what gives off the blue and purple radiance. That glow alone would give most Etzori pause to drink it. Etzos knows more about the history of the fountain than other cities on Idalos and its citizens are less likely to indulge, but I only say
less likely.
So yeah, quite a bit of Rhakros lore is outdated, but mostly only in a game-mechanics sense. What you ask about is all pretty much true as-is.
Did I miss anything?