They seem like better kids than Zuko. And I mean Aang and Toph are like brother and Sister.

Iroh would never give up on Zuko unless Zuko really proved himself to be beyond return. Toph already has parents and still loves them and they love her. I'm not sure where you got the conclusion that Aang and Toph are like brother sister, but I disagree. However, Iroh adopting Aang does make sense.

You just like making threads, don't you?

I haven't been very aware these past few months. i forget things way too easily. I'm getting kind of worried I may be coming down with some mental disease. Well, let's hope not. (I'm serious, not joking.)

Aang needs himself a father figure to help him grow up. Gyatso filled that role before Aang ran away. Now he's still just 12 and has the greatest destiny and responsibilities before him. Iroh would be a decent dad I'm sure for Aang and could teach him firebending.
Toph is a little different. She has a mom and dad in case you didn't notice.

Who almost treat her like a prisoner... So maybe she could be Iroh's adopted daughter.

Iroh will always forgive Zuko it seems. Heck it could be the last seconds of Irohs life and his executioner could be Zuko and Iroh would still forgive him and say that he knows there is good in him.

1) Iroh will never give up on Zuko! He has basicly adopted him as a son.
2) I think Iroh would become a valuable friend of Aang's, but not a father figure.
3) Althougeh Toph would make a way better daughter than Azula makes a neice, she will probly just always be really good friends with him. That, or she might get adopted in a sens, kind of like Zuko to Iroh.

The reason I say #3 that is both Toph and Zuko have over lieing problems.

1) Parent(s) don't understand them
2) Both think they can take care of themselfs without anyone's help
3) Both are independent
4) Both are/were hunted
5) Both are determined and/or stupporn
6) Even Iroh sid Toph sounded like Zuko

I gess we will see.