Planet without using Essence: Plot-significance prevents this from being the case if you want it for more than bragging rights. Magic doesn't quite work that way in all cases, but it's possible to lower the cost in exchange for time (and possible disruptions along the way). If you just want a planet that does something like resemble your face that will never house mortals, secret bases, or hide anyone on it, it's free. 7 ticks does sound like a decent lower bound on this sort of activity for such things as planets.
Ama: Noted, instructions received.
KI'Tork: As Andres said.
Spin-offs: Sometimes, I wish I could be a player instead so as to be able to participate in spin-offs and witch-hunts and all that manipulation YG tends to cultivate.
For the record, I have no problems with actual rip-offs, but I'm afraid I can't publish certain details kept hidden for some sort of misplaced security-through-obscurity thing or for player stability.
Anti-Void magic: There's no true inverse to Void magic, but the complete absence of magic probably comes close to its opposite. It's vaguely like trying to find the opposite of a pumpkin in the set containing all fruit in that the set would probably not contain the inverse. Of course, taking Void to mean "nothing," perhaps eldritch magic could be its own opposite. It has some out-of-context analogy to certain neutral mesons being their own antiparticles.
Attunements and the dust ring: It's not an attunement so much as it is an explicit power. While classifying various abilities into attunements seems like an interesting thing to do, it falls apart for many things. A clock, for example, is not an example of elemental or dimensional magic at work.
Luminees: T.M.I.! [insert emoticon here]
Spin-off in the likeness of the IoDaR minigame: I don't mind releasing this stuff (if I can even recall it), but much of it just borrows from Nethack and (idiosyncratic) preconceptions about d20.
Bellatores getting killed off (too much?) by the parasite-beasts: The reasoning's not visible, but it's no mistake. Of course, keep in mind that they probably slaughtered, say, ten times more parasite-beasts for every Bellator killed with no announcement, but being heavily outnumbered and continuously attacked tends not to be conducive to survival.
$$$Response
Dragon angels that shoot fireballs with extreme spread: 6-7E base
Make a terrestrial planet anti-Void: 20E+
Gas giant anti-Void: 30E+
Moon anti-Void: Typically 15E+
Star of pure Essence: Needs more detail; possible interpretations range from making starry decorations out of 1E each to making self-contained reactors maintained by Essence in addition to fusion