1) I get a BER of 0 and Q factor of 6.732e11, which makes sense. By changing the BER Analyzer to a Measured algorithm. This will give more accurate results since in your project you are reproducing the bit sequence at the output so the eye diagram has no source of noise.
2) The filters are usually defaulted to filter out 0.75*Symbol rate as the cutoff frequency. I was playing with it and then decided to just work with the bit rate. I don’t think any other components are using the information stored in Symbol rate, so it should not matter what it is set to.
3)I simply used a a time domain visualizer and markers to see how much delay the signal was experiencing. You could also try the clock recovery component.