**At the eaves, how far over the drip edge should the ice & water shield extend? **
In temperate climates I would cover all but the last 1/2" on the edge metal. In colder climates where ice damming can be a problem, put the ice shield on first and run it a couple inches onto the facsia board. Put the edgemetal ontop.
At the eaves, how far should the shingles extend over the ice & water shield?
Manufacturers all have their specs but in my opinion it doesnt matter too much as long as its functional and the roof material isn’t left long enough to curl and droop. I’d say anywhere between 1/2"-1" is good, 1/4" is too short and anything longer than 1" is going to curl later on.
At the rake, how far should the shingles extend over the drip edge?
Same as the eaves shrug. I’ve had people ask me to do 3/4" on the eave and 1/2" on the rake, like it makes a difference. If you’re smart enough to figure out why that 1/4" makes the difference in the grand scheme of the universe then why did you become a roofer, heh. I run it same as the rake, it’s simple, uniform and functional; anything else is just splitting hairs.
"…all shingles are flush with the drip edge."
This is dead wrong, no manufacturer specs this because it’s a potential water infiltration hazard. If you want to keep ladders from damaging the roof edge/gutter use a stand off.