Don't need to unbolt the motor mounts or tranny mounts.
I've never installed them but they can't be worse than pacesetters. I don't know what shorter dogbones would do for you on zzp headers, if anything shorter dogbones on a headered car brings the dp closer to the firewall or more likely to hit the firewall. You should be able to just drop the rear header in between the brake booster and rear valve cover and rotate it into final position. You don't need an 02 extension either with zzp headers.