A: The "*" signifies a unique ability or spell. This means that ONLY the class that the ability/spell is under may take that ability/spell. It cannot be used during custom classing unless a specific rule states otherwise. This also goes for Specializations. Unique specializations will always be marked with an "*" and any abilities in a non-unique specialization that has an "*" means they are unique to that Specialization.
A: We suggest a milestone based leveling system. This means once a story arc is complete you would give the players a level. This typically means every three to four sessions you would level the PCs. However, sometimes the group may complete story arcs incredibly fast. In these cases, you may have to wait until two arcs are complete. You may also decide to give additional levels throughout a story arc if players say kill a big bad evil guy, or destroy a whole planet. It is up to you as the GM to determine when it is best appropriate to distribute out a level, but the above system should help you out.