The enigmas 

  Resolved
   e1 - Welcome... Who ?
   e2 - Rebus... Who ?
   e3 - Crosswords... Who ?
   e4 - Amstramgram... Who ?
   e5 - Who is it ? Who ?
   e6 - Sudoku... ? Who ?
   e7 - Logically... Who ?
   e8 - Planisphere Who ?
   e9 - Peer To Peer Who ?
   e10 - Let's talk ... Who ?
   e11 - Music... Who ?
   e12 - Riddle ... Who ?
   e13 - Powerful... Who ?
   e14 - Easy ?! Who ?
   e15 - Planisphere ... again ! Who ?
   e16 - Try again ... logically ! Who ?
   e17 - Scrabble Who ?
   e18 - Mister and Misses ... Who ?
   e19 - Time series ... Who ?
   e20 - Where are we ? Who ?