Tilly. She seems to follow the scale Do, Re, Me, Fa, So, La, and then Ti.
Each barber must have cut the other's hair. The logician picked the barber who had given his rival the better haircut.
Elizabeth is drinking coffee. The letter E appears twice in her name, as it does in the names of the others that are drinking coffee.
$45. The pricing method consists of charging $5 for each letter required to spell the item.