I'm working on a blog post about typing the Lost characters, and I totally agree with your assessment!
Ben INTJ - incisive, overconfident, always has a plan, a system builder, and personal relationships are not his forté (even though he cares deeply about a select few)
Locke INFP - has a sense of wonder about the world, especially the Island. Constantly struggles with concepts of self-identity and purpose. Has strong awareness of others. Takes his time making decisions, and always has a lofty ideal in mind when doing so. He balances Jack in almost every way.
Jack ESTJ - he's a classic ESTJ as far as I can see, makes decisions quickly, stubbornly sticks to his convictions (even when evidence to the contrary is staring him in the face), has disturbing outbursts of emotion
Kate ISFP - She's impulsive, definitely a feeler but often keeps things to herself, until they burst out of her (kissing Jack, then running away). She is an idealist but is also a doer (like killing her dad to protect her mom) and she's also very physically inclined (tracking, hiking, climbing.)
Sawyer ENTP - at first I thought for sure he was an ESTP because of the conman angle, but now I'm not sure he was in it for the thrills - I think maybe that was just his mode of survival. I can see a lot of NT in his thought processes. Definitely a P, and definitely an E.
Rose ESFJ - Caretaker of everyone, outspoken, firm in her beliefs. Classic ESFJ.
Daniel INTP - he's a very typical INTP.
Miles ENTP - like an INTP, but the dude won't shut up
Jin ISTJ - so motivated by duty it's almost comical
Sun ISFJ - a nurturer, definitely an introvert, takes care of Jin even when she's planning to leave him.
Ana Lucia ESTJ - she's pretty much a female Jack, but way more annoying
Desmond INFP - dreamer, idealist, always searching for meaning and purpose but not always finishing what he sets out to do
Claire INFJ - Claire has turned fairly one-dimensional (mommy all the time!) which makes her difficult to type, but this is my inclination