1. The output voltage should also be initialized to the steady-state value, in order to avoid the saturation of the error amp.
The error amp output is clamped to such a value that will produce the maximum allowable duty-cycle. This maximum is based on other considerations: driver type, converter type (a buck can take 100%, but not a forward), etc.
2. You should run the simulation for one input voltage at a time. You then calculate the required duty-cycle for that particular voltage and initialize the error amp output to the value that will produce that duty-cycle.