Sounds great! Cream Lemon really does need more discussion. It may have bizarre stories, but some are very beautiful and sad, and a lot more than just perverted antics.
I love that piece in pop Chaser as well! Ah, I remember when I first heard it, I was telling myself, "gotta find this in the OST!" Unfortunately to my dismay... it wasn't there. Another piece I really enjoy is the music used in the beginning of Summer Wind. It's so fast paced and very cheery. I love the beat. Too bad that wasn't in the ost either! Sometimes I think maybe the creators used stock music for the series, and couldn't add it to the OSTs but what do I know. Maybe some Japanese dude has all the music we are looking for in some hard drive hidden away...
E-tude also uses Debussy's Abaresque, which is very beautiful for the setting the story.
Track 33 on disc 2 of the OST is another favourite. It's got a mysterious fantastical feel to it, like a dreamy state.
As for classical pieces, lately I had been thinking of going on a classical forum to ask the experts. Maybe they could shed light. If I get any help I'll post answers here too!