First: Arimidex should not be 'on hand'. It should be used from day 1. You're foolish to wait for symptoms to appear before using it. If you wait that long, you've fucked up. I can't believe you would actually consider running the cycle as written without running Adex from the start. The dbol alone requires an AI to be used.
The megabolic should be dosed daily, or AT LEAST every other day. Twice a week is not enough. You're going to have serious ups and downs with your plan as you've written it. The side effects will likely be tremendous. Pin every day.
I see no reason to taper back to your TRT dose. Going from a 380 dose to 220 in 1 week is not a big drop at all. When I go from a blast to a cruise, I drop from 1000-1500mg/week of gear down to 250 immediately. As long as you continue to dose your adex properly, this won't be a problem.
I don't see a good reason to taper the d bol up either. I would just run 40mg/day from the start, particularly if you've run d bol before and know how you respond to it.