I have had a Waiver since 2013. The agents are very courteous and recognize when you are travelling with your family. Do not split up as we did try this for the same reason you are worried about (my first Waiver when the kids were young), and we were told we needed to present to the Officer with all the members of our household that are travelling. In my experience, if the agent wants to ask more questions than the standard "where are you going and staying" and "how long are you there for", they send my spouse through to wait on the other side of the sliding doors with the kids. With the Waiver this has not happened often, but it has happened. I just need to answer a few extra questions before I can go through to join my family.

You should use the cbp one app, register before, and they will probably ask you to go for the second screening and take your picture and fingerprint.

I've had a waiver since 2000 and they have never asked me questions in front of my family pertaining to the waiver/ inadmissibility. I hand it to them with my passport, they usually look at it quickly, and asked the standard questions about where I'm going, where I will be staying and how long I intend to stay. I think you will raise more eyebrows by not passing through with your family to be honest. I understand the privacy aspect but personally have found the agents to show a great deal of discretion (even trying to keep their voices low when I'm renewing a waiver at the border when asking questions they need to).

Just go later than your family when lining up for CBP. There is not much you can do for them not asking you many questions. Sometimes they do and sometimes they don't. What you can do right now is to do it alone.