All else being equal, longer arms make you weaker at bench press. Say your pec attaches to your arm an inch away from your shoulder socket. If you could lengthen your arm, your pec attachment would still be one inch from your shoulder socket but, given that your arm is longer, you would have less leverage against the weight. Think of how a lever works. The longer the lever is on the pushing side of the fulcrum in relation to the length on the other side, the better the mechanical advantage is. If your arm is longer, the pushing side of the lever (pec attachment to shoulder socket) will be shorter in relation to the other side (pec attachment to elbow). You can think of it as if the weight has better leverage, not you. Based on the same principle, two people could have the arm length, but one person's pec attachment could be farther down the arm, closer to the elbow, giving them a mechanical advantage when benching. The attachment point of the other muscles, delts, and tris also probably has this same effect. On a positive note, you should be able to deadlift more, as longer arms will give you better leverage with this lift.
The amount of fast vs. slow switch muscle fibers in your muscle is a factor determined mainly by genetics. You may have more slow switch fibers, giving you better endurance but less explosive strength.
The amount of fibers activated by your CNS -is a huge factor in strength. For example when you restrart lifting again after stopping for a few months, you won't be all that much smaller, but you will be a hell of a lot weaker. In a few weeks you will retrain your CNS and regain all of your strength back rather quickly - and its not from growing mass. A lot of powerlifters training is focused on thier CNS, not on gaining mass. For example doing triples or doubles, using their lats at the start of the lift, and working on 'sticking points' on their lifts. Olympic lifters focus almost entirely on their form, to train their CNS. They don't look very muscular compared to bodybuilders, because CNS, not muscle size is a more important factor. It in fact takes a long time to learn Olympic lifts, like over ten years or more to gain the skill needed to compete.