The guy you like is Rap Monster, his role is the 'lift man' (?). He's the rapper of the group, you figured. But he's also the leader.
BTS stands for B ang T an S onyeondan which translates to Bulletproof Boy Scouts. People like to call them Bangtan or Bangtan Boys, also.
Doctor guy is JIN. A visual and vocalist.
The 'enemy' and 'energy' guy is SUGA. A rapper.
The race car driver is J-HOPE. A rapper and dancer.
Then Rap Monster, of course.
Then the red haired office worker is JIMIN. A vocalist and dancer.
Detective in the shorts is V. A vocalist.
Police officer is JUNGKOOK. The vocalist and dancer. (He raps occasionally.)