There are a lot of memorandums and policy guidance by the government to attempt to sort out a confusing situation regarding grandfathered 245(i) adjustments. Your daughter must submit a separate petition for you and for your husband, but there is much more to it. Please do go with an experienced immigration attorney. You can lose the benefit of the underlying petition if you don't do it right. You've waited all these years, don't lose it by trying to save a some money now.
This reply is intended only as general information and does not constitute legal advice in any particular case. This reply does not create an attorney/client relationship.
If you have met with several attorneys, why are you considering doing this COMPLEX process without professional assistance?
Most attorneys accept payments. Thus, please don't say you're doing it to save money.
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship. Also, keep in mind that this is an INTERNET BLOG. You should not rely on anything you read here to make decisions which impact on your life. Meet with an attorney, via Skype, or in person, to obtain competent personal and professional guidance.
If you married your husband after his brother's petition then you can not adjust after him, and must file with him, and if you came in illegally also then you both must pay the penalty. another issue is that your daughter as a U.S. citizen, must also file a separate I-130 for you too as there is no derivative category for parent of U.S. citizen. this is a complicated matter, and having consulted with several attorney you should find one of them capable of helping you in this process.
I would suggest you consider calling back one of those attorneys you consulted or find another. You are risking thousands of dollar in filing fees and potentially 1-2 years in delay if you do it incorrectly. Morrie is correct. You can't be derivative to an immediate relative petition. Your 21 year old USC must petition separately for both you and your daughter. You have to look at when the qualifying relationship existed at the time of the qualifying event for purposes of 245i. For general information, see http://www.mlawonline.com/blog/what-you-need-to-know-about-the-life-act-245i-in-new-jersey.cfm.
The family based petition with adjustment of status and the penalty is approximately $2500 per person in filing fees alone. If you make a mistake and that is thousands of dollars lost. Don't risk it. Find someone you trust and feel comfortable with to help you through it. Also, take a look at the June's Visa Bulletin, priority dates, for all but Mexico and Philippines, are December 2001. In other words, but for those two countries the priority date will come up soon, since your husband's brother must have filed before 4/30.01. For information on how to read the bulletin see http://www.mlawonline.com/faqs/how-do-i-read-the-family-based-visa-bulletin-.cfm. You may just be delaying the process and spending thousands of unnecessary dollars.
You needn't wait for your husband's approval and can apply at the same time. However, they will be two different applications.
This answer does not create an attorney-client relationship and is not meant to be relied upon as legal advice.
When (and if) you can file for adjustment often depends on critical details. If you are subject to the 10-year bar & have to seek a waiver, you shouldnt file until you have a "Qualifying Relative" -- this is not your daughter, even though she filed the I-130 Petition. You need a Permanent Resident husband. So he should adjust first. (If your husband is also subject to the 10-year bar, and neither one of you have the right "Qualifying Relative," then both adjustment cases will be denied). This is a good example of the many hidden traps along the way which show how important hiring a good immigration lawyer is.