I would like some clarification on this topic. Will longer pin length create more flare?
No. All pin length does is tell you how far apart the top of the weightblock and the center of gravity are. The pin distance from your axis point (pap) is what governs the amount of a balls flare potential is used.
What is the difference from a asymmetric vs symmetric ball with a longer pin?
An asymmetric ball has a "built in" preferred spin axis that tends to stay where it is marked on the ball, while a symmetric balls preferred spin axis tends to move into the area of the drilled thumb hole. As long as either of them has a manageable top weight for the drilling you want, you should be able to have a variety of drilling options with either one.
Also with a longer pin I believe there are more options for layouts? Any other info on this will be accepted.
A longer pin doesn't necessarily give you more drilling options. As a matter of fact, if the center of gravity is offline on an asymmetric, and/or the topweight is too high, it can limit your drilling options.
Do you have a specific drilling in mind? Or maybe a ball you're looking at has "odd" specs? As always, some ball specs lend themselves to versatility in drilling, and some can limit it quite a bit, whether the ball is asymmetric or not.