Based on the facts presented, it appears that your husband will require consular processing after the approval of the I-130 petition. Additional forms and documents will be required at the NVC stage. You really should hire competent counsel to advise and guide you through this process.
Its unusual that you did not receive a decision after such a lengthy wait. More facts are needed such as whether your entry to the United States was with inspection / with a visa? If so, it appears that you may refile for adjustment based on your current marriage. However, it would be prudent to enlist the services of an immigration attorney, who would help you secure your FOIA records [entire immigration file] before you proceed with your adjustment of status.
If your marriage is on shaky ground, you may be better of waiting the complete five years before applying for naturalization. You and your USC wife have to be married and physically residing under the same roof right up until your oath ceremony in order for your naturalization application to be approved on the three year basis.
You can file for divorce again. You will be able to seek custody and child support for your minor child, the fifteen year old. Alimony is discretionary and will be contingent on numerous factors such as the duration of the marriage; relative health, education and age of the respective parties; employment history of each party; etc. For any hidden assets, you would have to enlist the services of a forensic accountant and/or investigator. A consultation with an experienced family law...
You would have to complete the I-912 and send it in concurrently with your I-751. Substantiating documents for the receipt of food stamps and medicaid would also need to be submitted along with tax returns. Typically, when you or members of your household receive means-tested benefits, the fee waiver is accepted. USCIS's decision whether to accept the fee waiver petition is on a case by case basis so all you can do is submit it and see what happens.
Under current legislation, your spouse would be able to sponsor her. However, more facts are needed to definitively answer your question and explore your options for securing your daughter's permanent resident status.
The time frame for processing adjustment is approximately four to five months from submission to interview. The green card will only be approved once you have your adjustment interview. However, more facts are needed to answer your question(s). I agree with my colleague above. Since you have been in removal proceedings, your case is more complex than most; and you should be guided by a competent immigration attorney through the process of adjustment.
You should have received a receipt notice and a biometrics notice by now. Please ask your attorney to present you with copies of both as well as your entire petition. If s/he does not cooperate, you can contact your local state bar and file an ethics complaint.