I have not read Chris' s web page yet but I am sure it will probably say the same or something similar to what I am about to post. It is nice to see you put it all together now Chris.
1. No, actually mechanicals are more forgiving of shooting errors and/or tune on any given bow since their is no significant exposed blade area during flight.
1a. Yes, but only if it is a larger cutting diameter mechanical.
2. In my opinion, again the mechanical provided it has a larger cutting diameter. The energy needed to open the blades fully also tends to punch more of a hole in the deer rather than just to slice along the blades.
3. I have found Muzzys to fly relatively well compared to both mechanicals and other fixed/replacement blade style heads. In fact, they would be my head of choice if we are talking about non-expandable heads.
4. Again, provided we are talking about large cutting diameter expandables and adequate KE levels the mechanical will inflict more damage for the reasons I listed above.
But, just to relate the downside....mechanicals are not a cure all for a poorly tuned bow and relatively high levels of KE are needed for most of the ones currently on the market.