There is absolutely no reason for you not to use your p1 pedals so option a is silly. the simplest solution would be to get a trainer road subscription and use their workout creator to input your training plan's workouts. you could then pair your trainer and pedals in trainer road, turn on the power match feature so that trainer road compensates for any difference in your trainer's readings, and let trainer road control the resistance as you progress through your workout. trainer road can also upload to strava and training peaks. personally, i record my workouts on my garmin and sync it to training peaks like any other workout.

There might be a free alternative to trainer road that lets you input workouts and ride them while controlling resistance. I don't know, I've never looked.