1) No. The Chillswitch works opposite to the tails mode found on many delay and reverb pedals. If you set the SEND knob to ON, the INPUT jack is always connected to the SEND jack, so that a delay or reverb could be creating echo trails while the FX Loop is bypassed. When you click on the footswitch you will then hear the repeats.

2) The ENGAGE knob determines what happens when you press on the footswitch. When set to FX mode, you will hear the FX Loop when you press on the footswitch, otherwise when the footswitch is not pressed, you will hear the THRU signal from INPUT jack to AMP jack. When ENGAGE is set to THRU, you will hear the Thru signal when you press on the footswitch, otherwise you will hear the FX loop.