Have my previous choices influenced the behavior of other characters?

Question

I know that previous choices can change a lot of stuff in Mass Effect 3, ranging from dead characters to different endings. My question regards specifically if you can change the behavior of former companions.

For instance, I remember in Mass Effect 2 I had a long talk with Mordin about the genophage, and I think I eventually convinced him curing it might not be a terrible idea.

Now (in ME3) he not only helps me find the cure, but he was tipping Wrex off on where to find the females.

I also remember having long chats with Jack in ME2.

Now, it seems she's no longer angry at humanity and actually wants to do some good.

My question is: have my actions influenced this (and other) behaviors? Is it possible to influence such behaviors? I remember most companions in ME2 eventually "sat down" to have some serious talk with you about themselves. Did any of that make a difference, or would the story in ME3 be exactly the same no matter what I said to my companions in previous games?

Answer 1

In short: Yes.

Long but spoilered:

I haven't completed the game yet, so the list is incomplete, and I played from an everyone-loyal total victory ME2 save so part of this is theoretical, but from the way the cutscenes are set up, at the very least Grunt and Jacob's survival depends on them being loyal -- in both of their cutscenes they start out doing something suicidally heroic and badass in order to buy you time to get away... And in the version I saw, both of them manage to survive their attempts at self-sacrifice by being Just That Badass. The Mass Effect Wiki supports my theory.

Also,

The Geth/Quarian war can only end in peace if both Tali and Legion were loyal and the conflict between them in ME2 was resolved with a Paragon/Renegade answer. (among other things)

WRT Mordin,

Saving Maelons's data on the Genophage cure helps him understand Eve's health problems and saves her life during the cure extracton process -- if you destroyed it, she dies.

There may be others that I've overlooked,