Right above the front license plate.
No.
They are bolted to the underside of the hood and go through the rear hood vent. One small screw for each one.
YES.
Yes no difference. Wrong, A 66 Chevelle and a 65 are totally different hood styles. 66 and 67 are the same
Yes. It will bolt right on.
No. It will fit the 1966 and 1967 Chevelle only. A 1967 Skylark hood will fit if you can find one.
no
I have a 1972 225 and its under the hood by the passenger side winshield wiper...
yearone.com sells the stencil kit for the hood stripes.
It will bolt right on. You WILL need a headlight wiring harness from a 1970 as well since the '70 has 4 headlights instead of two like the 1972 does. A friend of mine did it. You cange the whole front (fenders hood grille etc.) and throw a 1970 rear bumper on and your 72 is now a 70. Your friend changed more parts than he needed to. The fenders and hood are identical from 1970-1972. The only body parts that are different are the headlight buckets, grille, and bumpers. Now you certainly can change everything, but it's not necessary.
No. 2 different body styles.