All of Fleck's songs/spells require an OIF (musical istrument of opportunity; -1/2). He doesn't have a Power Skill relating to Song Magic, so you might need to buy that or simply rebuild his songs without the :Requires A Skill Roll" Limitation.
This song isn't specified per se. It should be an Aid to PRE built around 60 Active Points, with an Area of Effect defined as "voice range." Limitations should be as other Songs in FHG II. Fleck uses it to bolster his companions courage when facing dungeon dangers.
This song doesn't have to indude laughter, it also could entrhall them due to the beauty of the music and versus.