Since no one has answered:
"It's all there..." is Frenchy to Henry and Jimmy.

Someone else post...

Q: Jimmy had never asked me to do a hit before

Henry narrating.
Q. "Big score comin' in..."

Since no one has answered:
"Big score comin' in" was Frenchy to Henry and Jimmy.

Someone else post...

Q: They whacked 'em

Jimmy to Henry.
Q. "Aw, don't f**k around with them."

A: Henry to Jimmy

Not sure if that's right, so TB can you tell me?

Correct! Please post a question...

Ok, I'll post one:

Q. "Con-gra-ja-LAY-shuns!"

...anyone please post???

Is that the parents to little Jimmy at his b-day party?

If so,
Q: "It shouldn't be a problem at all."

No, it was the guys to young Hendjry after his court date.
Answer to yours: "Shouldn't be a problem" is, I think, Frenchy to Henry and Jimmy.
If correct:
Q. "Where ya goin'? Fer a walk in da park?"

A: Paulie to Henry
Q: That means anybody!

Mine was actually Henry to Frenchy & Jimmy.

Answer to Irishman's:
Paulie to Henry

Q: "You may know who we are, but we know who you are."

Jimmy to truckdriver.
"It could be anybody" is Paulie to Henry.
Q. "And she says, 'Whatsa matter, you're always talking.' "

A: Tommy's ma to Tommy, Henry and Jimmy
Q: He thinks I'm paranoid

Karen to Henry.
Q. "Drinks are on...da house..."

A: Jimmy to Billy
Q: That looks like someone we know

Jimmy to the guys and Tommy's mom.
Q. "I swear on the kids I'm clean."

A: Henry to Paulie
Q: I've been bleeding for this caper...

Morrie to Henry.
Q. "Don't paint any more religious pictures."

A: Tommy to his ma
Q: ...he only did one

I give up, Irishman...answer?

A: Tommy to crew at the card table about the movie that Bogart made
Q: But you have to see your parole officer tomorrow

Karen to Henry.
Q. "I masterminded this thing..."

A: Maurie to Henry
Q: What the f*ck is the matter with you?

Jimmy to Tommy.
Q. "I hit a skunk, ok?"

A: Henry to Karen
Q: I've already been home...

Belle to Henry.
Q. "It's all there...piece of cake."

A: Frenchy to Henry
Q: I know you're waiting