1. This is why imbue amalgam is way too overpowered.
Really? Sounds to me like it's exactly the right amount of power, at least in this context. It simultaneously answers the question of how Autocthonia can ultimately solve it's own problems, and why it hasn't done so already: the solution requires ancient knowledge, which can only be used by an extremely powerful Apostate, applying vanishingly rare reagents, to willing mortal assistants, thereby transforming them into mutant super-cyborgs, who would then need to go around curing gremlins one by one, while maintaining some sort of quarantine so they don't get reinfected, instead of taking the easy route toward exploiting whole packs of them as a power base. And let's not forget the logistical challenges of keeping those modified humans alive! They'd have basic exalt-like toughness, but still need food, sleep, clean air, shelter from the environmental hazards of the Realm of Brass and Shadow in general and Blight Zones in particular, and if any loyal citizen of any of the Eight Nations, or agent of the Divine Ministers or, heck, even most of the more conventionally sensible tunnel folk or polar mutants, noticed any sign of this before step 5, they'd call it a terribly advanced Voidbringer cult fit only for high-priority extermination. Maybe the basic scheme has been attempted many times before, and always ended badly before it could even really begin.
If saving an entire realm of existence from insidious, Gigeresque mecha-cancer was safe and easy, everyone would be doing it. There ought to be some sort of grail quest involved, right? Long journeys, strange alliances, perils both physical and moral? This has all that, woven right in there inherently. The impossible cure for gremlin syndrome requires a
paragon among gremlins to turn back from the brink, choose to embrace virtue even while alone in the dark, and reconnect with humanity against all odds, because the only way out is through. That broad, flexible framework for a proper epic pulls itself together almost spontaneously, and all you can think to do is smack it apart with your nerf-bat, back down into the primordial slime, no fun allowed?
I've got a fix for the Eclipse anima power, too, on the off chance you're interested. Three straightforward changes, barely any mechanics needed: one, every charm has to be linked to an oath between the teacher and the student, with some conceivable condition under which the oath would break, the charm would be lost, and the student's 16 xp would be refunded. Optionally, it may include conditions under which the charm would be temporarily revoked, just as the Ebon Dragon can revoke Loom-Snarling Deception from the akuma of other yozis.
Two, the student doesn't have to be an eclipse-caste. Oaths and treaties including such a learn-foreign-charm clause can be established between other parties, even between groups with magnitude no greater than the Solaroid's Essence, and such an agreement might continue through generations as new members join a group and the old leave or die off - but no more than that initial magnitude can benefit at once, and if the deal's ever broken, or lapses due to one side or the other going extinct, it can't be restored without another eclipse anima touch to sanctify it.
Yes, this means un-exalted mortals can gain appalling, world-shaking power. (Chejop Kejack had
reasons to be scared of Salina's ambition.) They're still dependent on Exalted for
innovation, to create the best charms and the mechanisms by which such power can be distributed. They're also still squishy in all the ways those charms don't cover, and have no way to build proper paranoia combos. See, one of those existing clauses in the Eclipse anima power says, when you learn a charm with a Flaw of Invulnerability, you need to apply one of your own splat's flaws to it.
Third houserule, more of a fill-in-the-blank, is that the 'native flaw' for mortals and god-blooded is automatic failure against any attack which exceeds the relevant DV. Handy for bluffing, or against unfooable effects which don't include any actual attack roll (such as environmental hazards), but not much else.
2. Dreamscape tutor gem? Good luck. Not likely to find one. And not likely to even get access if it even exists.
I don't understand this appeal to improbability. It's just a two-dot utilitarian magitech artifact, minor variant on a standard formulaic template. Any starting Alchemical could easily have one of those without even needing to spend BP, then buy a daiklaive and reinforced breastplate forged from their favored magical material with the change left over.
The particular gem which is needed in this case happens to be very old, or possibly an accurate copy from older sources, and happens to mostly hold information with few other uses... but there could easily be dozens, or even thousands more just like it. Perhaps one of Creation's first Factory-Cathedrals produced a batch of them in order to bring newly-exalted Solars up to speed on skills they might need for pushing back the Wyld, then the Great Maker grabbed a few of those for his personal collection out of historical interest, and one of the Divine Ministers eventually plundered that titanic museum to find a suitable gift for an adamant-caste angel. No worse a contrivance than the old standby of a starting Solar justifying whatever item they don't know how to build themselves with an offscreen, pre-game visit to a previous incarnation's Shogunate-era tomb.
In fact, it's actually far
more plausible, since Autocthonia is all but overflowing with magitech infrastructure, and their history includes no Usurpation, Contagion, Balorian Crusade, or DB/Sidereal censorship to disrupt the continuity of institutional knowledge. The dreamscape tutor gem in question might have been recycled into some creche, as an archaic but pleasingly efficient device for cramming literacy and other basic job skills into young members of the Olgotary and/or Theomachracy during their otherwise underutilized nap-time shift, greater functions long forgotten until, hm, let's say some lunatic like Excessively Righteous Blossom just completely snaps, pulls a "my god, he's killed all the younglings," and pockets the shiny thing on his way out.
The really critical apostate, the one with the weaving engine, of course, gets to be the Palpatine in that scenario. After Luke and Leia have had their turn, then the Viator of Nullspace might play the part of the Yuuzhan Vong. Skywalker dynasty could even be Excessively Righteous Blossom's actual children, engineered to some eccentric 'perfection' through an Integrated Genesis System... wouldn't that make for such an interesting moment? Maimed in the aftermath of a beamklaive duel, clinging to a catwalk in a cavernous vent shaft, no more than an hour after the High Celebrant of Xexas was instructed to pray that some deal not be altered any further. Roll Join Debate and stunt your investigation-based Parry MDV with "that's not true, that's impossible."