The purpose of the comic is to include characters that they couldn't get into the live version because the actors weren't available. The characters you named-- Lois Lane, Clark Kent, Iris West, Kara Danvers-- are already in the live version of the crossover, so why would they need to again be featured in the comic?
I freaking love Felicity, and I like Wally and Nyssa as well, so I'm thrilled Marc found a way to include them. Those characters aren't just his favorites, they very popular with a big part of the audience too. I'm so happy he's pandering to people like me.