How are hemophilia, myocardial infarction (heart attack), and stroke related to blood clotting?

Opposites. Hemophilia is a defect of blood coagulation such that the blood does not clot. Heart attacks and strokes are a result of clots forming in the arteries feeding the heart and brain respectively. These latter clots can be formed locally due to damage to the blood vessels or an increased clotting tendency, or from clots that embolize from somewhere else in the body.
Hemophiliacs. May be at increased risk for strokes and heart attacks when receiving blood factors for episodes of bleeding. This is rare. Hemophilia does not protect against developing coronary artery disease.