Here I write you some possible solutions/suggestions to your questions:
1) The Simulink Data Inspector use as legend the signal name you assign in the Simulink model. Otherwise, if there is no name in the signal, it takes the name of the source of the signal (for example, if the signal comes from a Sine Wave block, the signal in the SDI will have legend "Sine Wave: 1". In your case, it seems you are plotting from a bus. If you want them to appear as single names, then try to rebuild the model with out using buses.
2) To increase the resolution the resolution, go to your Simulink implementation, then in the menu: Simulation > Model Configuration Parameters > Solver > Solver details. Once in there, you can modify the step size of your solver, so to get a smoother solution of your system (more points calculated).
3) Click on the signal you are interested, and in the top menu of the SDI, click on "show/hide data cursor". With this, you can move a cursor and it will display the time and signal value along the plot.
Hope this answers can help you in your questions!