How strong would the average Kaguya Clan member be?
On average they're stronger than the average ninja. They
were one of the strongest clans in the Land of Water during the Warring States period, but their overall potential is kind of capped by um, how do I put this gently? Just how stupid and inbred they are. Not that other clans like the Uchiha or Uzumaki aren't inbred (seriously, we see Uzushio once or twice in flashback and they're
all redheads, and both of Sasuke's parents have the sharingan), but they're not stupid, at least not Kaguya stupid. Canonically, they're enough to threaten Kiri shortly after the Third War, but they're not an existential threat to the village.
Pretty much this, actually:
I mean, the clan saw the full panoply of Bone Pulse abilities as cursed so probably just very skilled in taijutsu and other than that about average for most ninja and mercenaries.
Their taijutsu is exceptional and even members who don't carry the bloodline have above-average chakra reserves and healing abilities, similar to what an average Senju would be. Just, again, severely lacking in judgment and critical thinking.
I'm also curious if the All-Killing Ash Bones ability of Kaguya Ōtsutsuki have some lesser expression in the normal Kaguya clan. Like shooting out bones that are riddles with Osteoclasts that enter the blood stream and start dissolving bones across the entire body. Absolutely a hilarious T6-T7 ability I imagine but I'm always curious as to what the T5+ upper levels of the Shikotsumyaku can do.
Past Tier 5 it's all technically ninjutsu, though you've reminded me I should probably redo/repost the tech trees.
You're barking up
a tree with the idea of putting bones in bones to make bones bone while you bone bones, but it's not on track for All-Killing Ash Bones. Remember that Kaguya wasn't an alien, she was just a princess who was favored by the Ten Tails (whatever that means) here, or at least that's the common narrative, so maybe All-Killing Ash Bones isn't a thing. But if it is, it might not even have a place in the tech tree, especially if it isn't a pure expression of Shikotsumyaku.