the greasy substance around your skimmer is a combination of body oils and tanning oils that swimmers use to protect themselves from the sun. The oil collects there because of the suction of the pump. Try using a simple tile cleaner to remove it or a sponge type scum ball to collect the oils in the pool and you wont have nearly as much around the skimmer
It is called black algae. Your pool supply company can provide the proper chemicals to treat it.
Some are drains, some expansion joints
i dont think it really matters
The black linings on a basketball are called the seams.
The slimy mucus stuff in a pool is probably algae.
Most billiard mechanics use beewax or a water putter.
The Pool of the Black One was created in 1933.
You can stuff a stuffie with as much stuffing as it can hold without bursting at the seams. It's best to fill it until it feels firm and plump, but still soft and cuddly. Overfilling may cause the seams to break or distort the shape of the stuffie.
Too much iron in a pool can cause things to turn black. Speak with your pool shop about the right treatment.
If there are just a few spots and you do not wish to drain the pool you must first scrape the "head" off with a wire brush or algae stone and then apply a granular/powder chlorine directly on top of the spot. If the pool is riddled with the stuff it would probably be easier to drain the pool, scrape off the heads of the black algae and then chlorine wash the pool. Let the chlorine sit for a half hour before rinsing.
That would be a pool company.. Now there are dozens of coping styles and sizes, so take one of the old one with you..
You can not restitch a pool liner! It has to be replaced. If the welded seams are coming apart this indicates the liner is well beyond its life. Ken