On the doors, don't chase full coverage. The stampings and ridges are allready stiff, so butyl there does almost nothing. What actually matters is sealing the holes. Cut smaller pieces and put them over the service holes and cutouts in the inner skin so the door acts like one sealed enclosure behind the speaker. That did more for midbass in my old coupe than any amount of material on the flat sections did. So, deaden the big flat areas, seal the holes, and don't waste sheets riding over every rib. Roof is not overkill, but think of it differently. Butyl up there is marginal, a layer of closed cell foam is where the value is, mostly for heat and stopping that drumming tinny sound. If you've got foam already, use it up top and save the butyl budget for the floor.
On order of operations, you've basicly got it, but one thing to watch. MLV directly on top of butyl can actually rattle and buzz against it, which is worse than no MLV at all. You want a soft decoupling layer between the two, which is where your closed cell foam earns its keep. Butyl down, foam over it, MLV last. Keep the foam joints butted tight and taped so the MLV never touches bare metal anywhere. For the MLV itself, seams are everythign. Overlap the joints and seal them with proper MLV tape or even butyl tape, and do the same where it meets the firewall and wheel tubs. Sound will find any gap and sneak through, so a loose flapping edge basically undoes the work in that spot. Lay it in relaxed, don't stretch it tight, and let the carpet hold it. A few screws or clips through it into the floor is fine too, just put a dab of sealer under the fastener head so you're not punching leaks in your barrier. Last tip, roll your butyl properly. Keep rolling untill the roller marks go flat and shiny. Half pressed-down butyl is where the squeaks come from two years later.