An NPC isn't an awful way to go, but I would prefer something different too. A familiar is certainly viable. I'd say it's even possible to go Ranger and have a Beast Companion, or perhaps even better, Shaman multi-classing with a Spirit companion.
There's more than one way to skin a cat... or in this case, "skin" a spirit dragon.
There is some wiggle room on the sassy fellow. But if one is designing a character for "D&D" with a "guardian spirit." I think with all the ways that can be a real feature of the character ... we have named three ... the NPC option sounds like an "I don't want to try." answer aka cop out.
I think her intellect can be cast as cunning alah charisma.. stats are a bit malleable... as long as actual intelligence still good same with dex... needs to be solid. Con and Strength dont need to be ultra good.
Wierdly I keep wanting to do at wills from the fighter but that is probably just my comfort zone talking... I find them easy to skin various ways.
The Alchemical Opportunist sounds like a possibility heh (maybe more necessary than the Quick Familiar ,, even Improved Initiative just sound right.
====== Created Using Wizards of the Coast D&DI Character Builder ======
Mulan, level 1
Human, Bard
Build: Cunning Bard
Bardic Virtue: Virtue of Cunning
FINAL ABILITY SCORES
Str 10, Con 10, Dex 13, Int 16, Wis 13, Cha 16.
STARTING ABILITY SCORES
Str 10, Con 10, Dex 13, Int 16, Wis 13, Cha 14.
AC: 17 Fort: 11 Reflex: 16 Will: 15
HP: 22 Surges: 7 Surge Value: 5
TRAINED SKILLS
Athletics +4, Arcana +8, Insight +6, Perception +8, Bluff +8, Acrobatics +5
UNTRAINED SKILLS
Diplomacy +4, Dungeoneering +2, Endurance, Heal +2, History +4, Intimidate +4, Nature +2, Religion +4, Stealth +1, Streetwise +4, Thievery +1
FEATS
Bard: Alchemist
Human: Quick Familiar
Level 1: Arcane Familiar
POWERS
Bard at-will 1: Guiding Strike
Bard at-will 1: Jinx Shot
Bard daily 1: Stirring Shout
Bard encounter 1: Blunder
Bonus At-Will Power: Cutting Words
ITEMS
Ritual Book, Adventurer's Kit, Implement, Wand, Light Shield, Longsword, Hide Armor
====== Created Using Wizards of the Coast D&DI Character Builder ======
Very not optimized... she gets toasted on fortitude (which is certain where in the show she was seen as weak)
Some effects described as arcane she is using more old fashioned smart trickery..
Shrug... its an attempt and at least somewhat satisfies... so that is a success... the dragonling familiar actually allows a burst effect centered on Mushu... (Now that is what I call Mongolian Barbecue). Which might require some multiclassing.... after a few levels... wouldnt mind that 17th level fighter disarm just because its a vivid scene in the show.
Yup its hard to be sure what somebody will be willing to put up with in divergence (the trained in Arcana is a bit wierd feeling a character purist would say diplomacy makes more sense etc.... ).