Need help understanding the mosfet trailing edge Dimming
I have a lot of questions about your circuit and your answers have not really shed much light on my questions. There really does seem to be a major disconnect between what you expect and what you drew in your schematic. Maybe you can look at the picture I drew and let me know if it is correct, or if not, you can update it to make it correct.

Based on the schematic I can say with confidence that any time Q1 is on, Q2 will also be on and vice verse. This is because the gates are tied together, and the sources are tied together. So Vgs of Q1 will always be equal to Vgs of Q2. Vgs is the voltage that controls whether the MOSFET's are on or off.



Assuming the GND in your schematic is NOT connected to the AC GND (let me know if this is wrong!), then it is impossible for current to flow through the body diodes of either Q1 or Q2. The body diodes point in opposite directions and are in series. So when the MOSFET's are off there is no current path. And when they are on, the body diodes are shorted by the Rds of the MOSFET. MOSFET's are bidirectional devices. When they are "on," current can flow in either direction from drain to source or source to drain with the same low resistance.

As far as choosing values for R3, C3 and L3 goes, it is not clear what you are trying to accomplish with them so I am not able to assist with that.