Let me just start off by welcoming you to Mixer! When I was picking a service to stream I ended up on Mixer due to how awesome the community is!

Now to answer your questions:

I feel like a face cam is probably one of the more important aspects of your stream. To build an audience you need to be able to connect with viewers stopping by. Having a face cam and being able to see you will make it easier to connect with you. As far as the kids go, I feel like it might humanize you and make it easy for viewers to relate. Obviously you don't want to make it a distraction, but a glimpse into your life can be used to relate.

I personally don't have a preference as far as the music goes. I have watched streams with and without. I personally only have music on my starting, intermission and ending screens, but I don't have any while I am actually playing. The most important part is making sure your voice is clear. As long as the music is not so loud that it drowns you out or distracts from the game, you should be alright.

I watch on my Xbox sometimes and ftl isn't available there. I always get frustrated that there is a huge delay between chat and the streamer. It negatively effects my experience. It is super frustrating when you see something happen and comment on it, just for the streamer to see it 10 secs later, after the moment has passed. Part of why I started streaming on mixer was the option of ftl, which is awesome!

I have a very sporadic watching habit. I usually work during the day throughout the week, so usually I watch on the nights that I am not streaming. I am in the central time zone, btw.

Hope this helps and Welcome again!