if both of your and your wife's I-485s are approved, but your child's I-485 is denied, your child still can file a new I-485 based on your wife's approved I-485. So, nothing worried about.
MY NEW QUESTION: my laywer said it is nonsense to withdraw the 485s based on my wife's I-140 because me and my wife can get the green card earlier if USCIS approve the 2 485 and interfiling (I-485 relink) will get my case complicated and may not work. how do you think?
-I don't suggest you to withdraw the I-485 either and that is only your option. The interfiling of I-485 will work well (many cases have proved that) and just try it and follow up by calling USCIS to make sure the interfiling has been made. Of course, filing a new I-485 is also another option and it will make the case simpler, but it cost your filing fee and deplay your child I-485 approval due to new processing of I-485 (e.g. biometric, background check, etc.). By the way, as I said before, even if your child's I-485 is denied, she still can file a new I-485 based on your wife approved I-485 later unless your child will reach 21 years old very soon.
Anyway, it is up to you.
Now my laywer recommend us to file a new 485 for my daugter based on my wife's I-140 (which will be current in August 2012). Do you think this is a good way? My concern is if me and my wife's 485 get approved before UCCIS received daughter's new 485, will my daughter be out of status?
-Yes, and her status will be AOS if her I-485 is still pending. If her I-485 is denied, she can file a new I-485 within 6 months as long as your wife PD is current.
if not, what is my daughter's status after me and my wife's 485 get approved (currently my daughter is H4 dependent on me)?
How long it will take to get my daughter's 485 approved after me and my wife's 485 get approved?