Any form of incline pressing work. Add in incline dumbell flyes. Start off always with incline work or make your chest workouts all incline movments, eg. incline smith bench, incline db bench and incline machine press together with incline flyes if they're proving real stubborn.
Yeap.
A lot of trainees are more advanced in their chest strength than they think. Question you need to ask yourself is, are your other bodyparts even up to par with your chest in the first place? Even if your other bodyparts are progressing, they need to be compared to the current progression of your chest. If you bench press is currently let's say 70kg and your barbell row is less than 50kg, which is supposed to be near your bench press strength, then you need to work on other bodyparts first.

Lol, i don't get it with some guys and their ego muscles. All they think about is chest, chest and chest. If your other bodyparts aren't strong enough to lend support for chest strength, reprioritize.

You'll always hear people whining about their arms and chest being not up to par. You rarely hear people complaining about their back or calves or quads. All these make up the complete package.
You'd be surprised. Less than 35.