If you have other quality evidence, I wouldn't wait more than a couple weeks. The 2023 tax return can be uploaded later or presented at an interview (if you are so "lucky"). As the others have said, wait a day or two into the 90 day window to submit the I-751 package. Good luck. It gets much, much easier after Removal of Conditions. Keep your eye on the target----getting out of the grasp of USCIS!!
It could be a few days to a couple weeks. Be aware that you must also request an expedite from NVC after you receive a DOS case number. The consulate will them either accept or decline to expedite the case further.
A Police certificate from the US is not needed. USCIS and the consulate will run their own background checks. You will, likely, need the court paperwork.
I would immediately contact the consulate and ask them to process the I-130, and schedule both interviews together. They have the discretion to directly process the child's I-130 rather than going through USCIS. They can then reschedule wife's interview together with child's interview.
I assume you know that Adjustment of Status will mean no work and no leaving the US for at least 3 to 8 months. It will also mean no green card for some time...maybe a year.
"D/s" means "For the duration of stay". Yes, the dated stamp is the endorsement. That visa is now a temporary Green card for a year or until the plastic one arrives.
If the visa expires, the consulate can, at their discretion, re-issue it. However, it will mean another medical exam...and possibly another interview. Good luck in getting her CFO done on Monday. She must enter the US prior to visa expiration.
I haven't seen them enter a "D/S" before. However, I don't think it is a problem. The stamp indicates you entered on 2/1/2024. The endorsed visa acts as a full-fledged Green Card for a year.
BTW, I have seen them put a variety of dates.....I think you are fine.