Siddh, the first thing to mention is that Avalon don't do 'one off' or special orders on their speakers, so you wouldn't be able to order the ED with the CELL concept midrange & tweeter. And I wouldn't recommend modifying a pair of ED's. For one thing, you wouldn't get your money back & the Compas' drivers are a different shape/size, so they won't drop into the ED.
Fwiw, I strongly considered the Eidolon Diamond myself & discussed options with Lucien at Avalon. His recommendation was the Compas Diamond which is a more dynamic and overall superior speaker than the ED & employs Avalon's latest thinking.
Fwiw, I strongly considered the Eidolon Diamond myself & discussed options with Lucien at Avalon. His recommendation was the Compas Diamond which is a more dynamic and overall superior speaker than the ED & employs Avalon's latest thinking.