Maybe it's just their own breath weapons critters are immune to.
For the 1st-level spells, shouldn't the domain spells just work for her cleric spell slots? We didn't give her the ability to cast them as sorcerer spells, and there seems no need to since she has cleric casting anyway also.
Dang it, as you pointed out I omitted the "Can also cast cleric spells as arcane spells." when writing what cleric spell domains she has access too. I was always assuming she had the arcane-casting cleric spell ability that many true dragons have. She combines the abilities of ALL chaotic dragons, and some chaotic dragons can do that (i.e. the Amber, Brass, Copper and Red).
I'd just perform the following tweak:
Spells: Pearl is a 20th-level sorcerer and a 20th-level cleric. She can also cast cleric spells and spells from cleric domains as arcane spells. Pearl has access to all the domains available to the chaotic dragons she rules (For the amber, black, brass, copper, amber, red and white dragons, these are Chaos, Destruction, Earth, Evil, Fire, Knowledge, Luck and Trickery). In her natural form, Pearl can cast her spells with but a word.
We can still do protection from good and true strike. Then maybe shield instead of entropic shield. That seems like the closest match. So we'd have protection from good, ray of enfeeblement, shield, true strike, unseen servant.
I'd find those changes acceptable.
I'm actually not that bothered about whether the protection is to
good or
law - although
protection from law is arguably a better thematic fit to her as the Ruler of Chaotic Dragons.
At 2nd level, maybe blindness/deafness, cat's grace, detect thoughts, hideous laughter, mirror image? Thoughts?
The 2nd level spell choices look fine, but we'd better settle the question of arcane cleric spells first.
If she does have cleric access, there are a few juicy choices to consider for the 1st level sorcerer casting - like
divine favor or
shield of faith instead of the
true strike or
shield/entropic shield - although we should always have the question "would that make more sense as one of her standard cleric spells" floating in the back of our minds.
We'll need to consider her Domain spells eventually whether or not she can cast them as arcane spells, so it seems pertinent to list them now:
1st Level Domain Spells:
Chaos:
protection from law, Destruction:
inflict light wounds, Earth:
magic stone, Evil:
protection from good, Fire:
burning hands, Knowledge:
detect secret doors, Luck:
entropic shield and Trickery:
disguise self.
2nd Level Domain Spells:
Chaos:
shatter, Destruction:
shatter, Earth:
soften earth and stone, Evil:
desecrate, Fire:
produce flame, Knowledge:
detect thoughts, Luck:
aid and Trickery:
invisibility.
3rd Level Domain Spells:
Chaos:
magic circle against law, Destruction:
contagion, Earth:
stone shape, Evil:
magic circle against good, Fire:
resist energy* (fire), Knowledge:
clairaudience/clairvoyance, Luck:
protection from energy and Trickery:
nondetection.
4th Level Domain Spells:
Chaos:
chaos hammer, Destruction:
inflict critical wounds, Earth:
spike stones, Evil:
unholy blight, Fire:
wall of fire, Knowledge:
divination, Luck:
freedom of movement and Trickery:
confusion.
5th Level Domain Spells:
Chaos:
dispel law, Destruction:
mass inflict light wounds, Earth:
wall of stone, Evil:
dispel good, Fire:
fire shield, Knowledge:
true seeing, Luck:
break enchantment and Trickery:
false vision.
6th Level Domain Spells:
Chaos:
animate objects, Destruction:
harm, Earth:
stoneskin, Evil:
create undead, Fire:
fire seeds, Knowledge:
find the path, Luck:
mislead and Trickery:
mislead.
7th Level Domain Spells:
Chaos:
word of chaos, Destruction:
disintegrate, Earth:
earthquake, Evil:
blasphemy, Fire:
fire storm, Knowledge:
legend lore, Luck:
spell turning and Trickery:
screen.
8th Level Domain Spells:
Chaos:
cloak of chaos, Destruction:
earthquake, Earth:
iron body, Evil:
unholy aura, Fire:
incendiary cloud, Knowledge:
discern location, Luck:
moment of prescience and Trickery:
polymorph any object.
9th Level Domain Spells:
Chaos:
summon monster IX* (chaos), Destruction:
implosion, Earth:
elemental swarm* (earth), Evil:
summon monster IX* (evil), Fire:
elemental swarm* (fire), Knowledge:
foresight, Luck:
miracle and Trickery:
time stop.