No, Wormerine is right, those are companion quests, it gives more backstory & interactions to the companion you are traveling with. This gives additional motivation on who you want to travel with, you want to travel with Lae'zel for the creche which she's gunning for or one of the other companions with there own personal crap and motivations.
You have to chose, you don't get all the options.
I am going to have to agree with this stance and there are a couple reasons why:
1)
from a roleplay standpoint the Tieflings don't seem to know what a Githyanki is (at least the ones you run in to) the first two say "Zorru was right, yellow as a toad and twice as ugly" and then further dialog they call Lae'zel "it" and "thing" (hurtful :P ). Next when you meet Zorru with Lae'zel in the party he recognizes that she is of the same species/ race as another Gith because they look similar, but he doesn't say "Oh crap more Gith!" nope he proclaims "Oh no another one!" So, going to him without Lae'zel and saying to him "I am seeking a Githyanki Cresh," something you know nothing about yourself at this point other than what Lae'zel has told you. He is going to look at you and say "I don't know what that is..." keep in mind Lae'zel tells you Zorru has "seen" Githyanki not that he was attacked by them. So IF you were to go see him and say "I heard you've seen Githyanki, I need to know where..." he wouldn't know what you are talking about with out a dialog option
you give a detailed description of Lae'zel... so you see it becomes very convoluted very quickly... do able, but a tad convoluted... In the case of Spike there is no two ways about it... you need Wyll in the party to get any information relevant to Wyll's story... First time you can hear Spike's name as a character of interest is at the windmill, but no matter how much you press Wyll on the subject the MOST information you get out of him is that Spike is the goblin that took his eye and that Wyll wants to pay him a visit. It isn't till you find Spike that you find out that Wyll isn't just out to kill the little snot rag, but that he is searching for Mizora. So... Without Wyll there for the interaction the only real dialog that could be added would be something along the lines of "The Blade of Frontiers says hello"
attack. The same holds true for other interactions. Parts of Shadowhearts story are just going to be lost if she's not in the party with you because without her there to interact with environment certain cut scenes just don't happen.
2)
from a relplay value stand point if you want to see all their stories in full you will have to play the game through multiple times (and likely make different choices than the previous play through). Frankly I love a game with high replay value and with the final product rumored to have somewhere between 6-16 possible companions it would be impossible to get the full measure of all their stories in one playthrough. So, you may as well pick a few you ... I won't say like... find interesting and find out what happens. At the same time talk to companions you leave in camp getting what bits of their story you can in order to decide who you want in your next play through. ^_^
