Why is the Leviathan if the Ocean blue and for the Coast red? Is there a reason behind? I prefer the blue.
The trigger that causes the Leviathan to move (if it has appeared) is the blue monster icon. The red icon is a tie-in for those using the dragon (from Princess and Dragon) and who may have placed a volcano earlier in the game - hence the inclusion of an island volcano tile. The icon is placed on a coastal tile, and my assumption in creating that specific tile was that someone on that location had seen a dragon flying across the water. Of course, that same person might also see a great sea monster out to sea.
Same question related to the ships. The Ocean has wooden and the coast tokens? Why? I prefer wooden figures.
When we (squiffything and myself) created "Sailing The Seas" we decided to include the ship tokens. Subsequently I investigated options of using Catan ships and other pieces from the Spielemateriel website, and later I was kindly sent a set of 3D printed galleons which are the "best looking" of the different options, and I used them when playing with STS and the STS:Trade Routes expansion in my game. If people prefer to use the original tokens, ship pieces, or even coloured cubes to represent the 3 ships, then it is up to them.
Are the harbours of the ocean equal to the ports of the coast? Maybe that is the reason for the different symbols?
When "The Coast" was first published, STS didn't exist, and there was no concept of "Ports" other than as "cities on the coast". Their only function was to be the starting point to develop bigger cities. The addition of the "Catch Of The Day" expansion was simply to replace some of those coastal city tiles with an extra feature. With STS, an extra function for any coastal city (or village or monastery) was added - i.e. a place where treasure could be returned and sold for profit - and signified by the anchor symbol. Subsequently, I made some of the coastal cities more elaborate by adding sea walls. But despite the design variations, all of the coastal cities have the same function across the various Coast and STS expansions - with some having extra functionality in being the end off a Trade Route.
This also applies to my recently published "Coastal Cities" tiles. Those with a specific anchor symbol may be used as a destination for "cashing-in" a treasure chest when playing with STS. Otherwise they are just the starting point for creating larger cities.
Recently, oldbonz and meepledrone created some "Ports" tiles, which may be placed against any section of coast, as a sort of "Joker" or "jolly" tile and roughly akin to The Abbey tile.
The bottom line is that these different aspects to the game have developed over time and we have tried to integrate them as best we can with older elements.
Hope this explains it to your satisfaction!