1) AP players achieve things generally faster. Due to a variety of ways to earn money/ AP Items ingame, the gap between AP buyers and non-buyers is smaller than in many other games though.
2) No that is not possible. Guild towns cannot be conquered or anything.
3) Yes, we have something called Territory War. In there, guilds fight over certain areas. The members of the winning guild can collect some money and boxes every day in the area and also get a small exp/cp boost in it.
4) There are 1-3 dungeons on every map, yes
5) It is very easy from Level 1-30, almost boring for many, but then it starts getting tougher and tougher, even in PvE. If you are skillful and have at least some decent gear, you're fine though.
6) Yes you do, you get a pet at lvl 5 and a mount at lvl 30 for free via Ingame Quests.
7) The variety is quite big imo (you can check the archive ingame to see a list of pets and mounts). Almost all Mounts/Pets come from AP or the Eden Crystal Altar though.