C. Green Emerald 'Queen' is a pale green with maroon spots and a pink and white lip. It is pure Cattleya (by any definition of Cattleya), no Blc. and Slc. involved.
From OrchidWiz:
C. Elizabeth Mahon = intermedia x Little Angel
C. Little Angel = Obrieniana x loddigesii
C. Obrieniana = x dolosa x loddigesii
C. Thospol Spot = Bimayothin x aclandiae
C. Bimayothin = Priscilla Ward x aclandiae
C. Priscilla Ward = granulosa x forbesii
Even without a program like OrchidWiz you can always work through a family tree step by step at:
The International Orchid Register / RHS Gardening