In Coach 6 this is possible via Tools > Library Filter, where you can select which sensors and actuators should be visible in Coach.
In Coach 7 it is not possible to make your own selection from the entire sensor library.

No, but by displaying a Meter you are able to view the magnitude of a signal in real-time.

No, this is not possible. However, you can obtain more data points through interpolation. Use the option Process/Analyze > Smooth for this and choose ‘Spline’ combined with ‘Replace data’.

Every interface has a maximum number of data points that can be collected. If this maximum is reached, the measurement stops automatically, even if a longer measurement time was set.
The maximum is 16.380 points for CoachLab II, 32.760 points for older models of CoachLab II+, and 500.000 points for the newest CoachLab II+ models with updated firmware (and Coach 6.3 or newer). The number of data points that can be collected at sampling frequencies higher than 10 kHz is also limited. In this case, the internal data buffer of the interface cannot be emptied quickly enough and the measurement will stop once the buffer is full. For CoachLab II+ this corresponds to a maximum of 32.760 data points.

To gather more data points than the allowed maximum, the option Repeat from the Measurement settings can be used.

First check the measurement settings to verify that the correct time and unit have been entered. It is also possible that the length of the time-axis in a diagram is shorter than the measurement time. This makes the measurement look shorter than it actually is. Use the option ‘Zoom to fit’ to show the entire data range.