color conditions on xy scatter chart and show/hide series and legend name for true/false

Hi there everyone

I got a few questions here that I'm very much hoping you can help me with ...

1st: I'm looking for a way to change the color of this month line and maybe even make the line bold ...

2nd: if there's no data in the series I would like to have it not showing both the line as well as the Legend name (or if I've chosen not to show that line with a checkbox)

finally I got my data set up without codes so that I can get gaps in the line to better give a visual picture of the data.

OH and then I'm hoping you can help me get some better informations on the points when you hover over them ... I need to get one more number showing (Insulin) next to the last number

(Data is in sheet2)