The coloration and patterning doesn't quite make sense, if it's meant to be camouflage.
Judging by local conditions (genus group flora ignored for now):
Barlowe Temperate Rainforest:
Rusty-red soil
Rainforest Carnofern: saturatd reddish-brown.
Obsidian Shrub: Black.
Two cryoflora species: Cyan/glassy.
Clusterspades: Purple.
Tlukvaequabora: brownish-grey.
Barnline: trunks: dark saturated brown.
Obsidibarrage: black.
Qupe Tree: dark reddish-brown trunks.
Obsiditall: black.
Sweet red spade: bluish-purple/indigo.
Some genus group options that might make its coloration plausible:
Brown-tipped larands, in high abundance (slightly reddish brown; slightly off, but fine if it has no predators with color vision)
Tepoflora (dull brown)
The fact it's nocturnal means the need for a good match is decreased, assuming it has no predators adapted specifically for low-light color vision, assuming that is even possible. However, during the daytime, if it's out in the open it will still need decent camouflage, or can wake up very quickly to evade predators that would try to attack it while it's sleeping. (Or keep a "daytime watch" of sorts in the herd.)
There is the possibility these are, like fawns, adapted to blend in with dappled sunlight, so as they sleep in the open they are camouflaged. However, the tall blackflora trees wouldn't leave dapple-patterns in the same pattern many deciduous Earth trees do: they're shaped like palm trees. That still brings up whether it can blend in with Sweet Red Spades or Clusterspades. (And it definitely wouldn't blend in with the cryoflora.) If decaying leaf litter, whether of a particular kind of flora or all of them, can be assumed to be a drab greyish-brown, then it might be decent camouflage....in winter. Fresh purple or black leaves would likely fall down directly onto drab-colored layers.
The easiest solution is to say this is just a special impractical coloration for the males. The second is to say they're so fleet-footed, quick to wake up, and have members of the herd on guard duty that it doesn't matter if their camouflage is not quite right. The third is to say they have good color vision and specifically seek out areas where they blend in (most notably avoiding cryoflora), though that would require either nighttime color vision or knowing the colors of everything when it's daytime, despite being nocturnal.
There are some typos, too, but this is enough for now.
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EDIT:
Scientific Queries:
Unless this eats some combination of fallen leaves or the leaves of saplings specifically, it wouldn't be able to reach those trees' leaves. Some specification of the needed size range of its trees in its diet would be useful. For comparison, white-tailed deer and sika deer do seem to eat freshly fallen leaves, if apparently on winter or when food is limited.
"but for an unknown reason are attracted to Wolvershrogs." Out-of-universe, it's obviously because it's the "Santa Claus shrog". In-universe...it's probably because they eat exclusively aquatic creatures with a little fruit, berries, and other vegetation, so they're no threat to these, even if they're huge carnivores. Great Leotams ate the ancestor of the ancestor of Prancerhorns, so logically they'd eat these, too. Wolvershrogs and adult Great Leotams are the same size, and so it's possible Wolvershrogs would view them as a threat, especially since Great Leotams do eat Longjacks, which are also in Lutrasoricidae. In other words...foraging in Wolvershrog territory means Wolvershrogs won't eat them, but may scare or fight off Great Leotams that get close. It would be similar to a species of hummingbird nesting near hawks because hawks keep away jays, the hummingbird's predator.
Wait...if they're actual antlers, they would be shed. That's unusual. Some elaboration of the physiology is in order.
Typoes and Language Errors:
Obsidibombs are extinct. You probably meant Obsidibarrage.
"showing off their antlers": show off.
"Rainforest" rainforest.
"They have grown larger and has lost another butt-nostril to help it sing its own unique song to mates"
"has lost": "have lost". "to help it sing" suggests purpose rather than function. It's important to make the distinction between each when discussing biological matters. Therefore, I suggest "which".
"Their relatives the Pronghorn Strider" That confuses the plural.
"Prancerhorn's are": "Prancerhorns are".