Q3. Free companies are the FFXIV equivelant of Linkshells or any other MMO's guilds. Grouping of players organized for social/progression purposes. Unlike linkshells, you can only have 1 FC at a time.
Q4. The Jobs i mentioned earlier are unlocked by having the main class at 30 and the subclass at 15 so for example in order to unlock Paladin you have to have GLA 30 AND CNJ 15, You can probability just ask in game what makes what.
Q5 Yes PS3 has a delay compared to PC, this is technical and not a reflection of your PC or internet connection.