Cleon
Legend
I just don't see the point in having such a complicated Mirror Magic ability complete with a table of what mirror magic spell levels work where in the Outlands. It's overkill for what should be a pretty basic creature, especially since mirror magic is "a very minor sort of utility-centered magic craft."
The description of mirror magic as a "minor" magic craft doesn't match very well with the actual scenario, which includes all kinds of impressive magical devices. Ranging from mirror-charms that kidnap people, summon monsters, create magical duplicates à la a mirror of opposition and create a self-repairing artifact able to create copies of every book in existence and store them in an infinitely large extradimensional space.
If that's minor magic, what would the Kamerel consider major magic!
As for the table, all spellcasting in the Outlands is affected by the Spire's counter-magical nature to a degree that varies with level and distance from the Spire.
The proposal boils down to just using the standard "Impeded Magic" trait for mirror magic (Spellcraft DC 15+level) instead of the Spellcraft DC 35 the Outlands normally applies.
I wouldn't write such a complicated ability for it.
But what I don't really understand is why you don't like my proposal in post 20, which basically does the same thing your proposal does but with a lot less extra text.
Shall I list the ways.

The biggest problem is that Kamerel are incapable of casting "normal" spells. The adventure states quite clearly they're incapable of understanding them.
I prefer having them cast spells that operate like arcane magic, but are specifically not arcane magic.
The proposed "Kamerel are able to cast arcane ? spells up to X level in the Outlands" makes no allowance for Impeded Magic Spellcraft DCs, which I think should apply to Mirror Magic, since it appears to be restricted to some extent by the Spire.
Speaking of said restriction, the adventure says the Kamerel can't cast any spells within 100 miles of the spire (just like any other spellcaster). Your proposal would allow them to cast spells "up to X level" even if they were standing directly beneath the Spire.