Weight loss relies about 75% on diet and about 25% on exercise for most people. Simply exercising more without changing diet is a poor way to lose weight, even a lot more exercising!

It depends. This is usually true if you are very overweight, but if like many people you are skinny fat or only slightly overweight (~5 lbs) it's usually not necessary to reduce your calorie intake. Exercising more and ensuring your getting the right macros is enough

People have a base level metabolism based on whether their body's natural form is an endomorph (high fat), ectomorph (low fat, low muscle), or mesomorph (high muscle). While few people are purely any of those, most people have one that fits their body more than any other and that is their natural form.

Metabolism is incredibly complicated and mostly genetic. Although it can be changed (slightly) by your diet or exercise habits, it has nothing to do with your body type. Your body type is usually a result of your metabolism, not the other way around