These clean vox are giving me hell. Got tips on how to get them to blend better?

The first thing I notice is the singing is completely off key. If you're using some sort of auto tune plugin you need to adjust the notes it's allowed to use so you don't break out of the proper key. And from what I hear you are using auto tuning. Everything else sounds great though.
 
Wow. Melodyne those god-awful sung vocals, or something. Fix 'em.
I'd re-EQ them too to make them sit better for starters.
 
Ah, makes more sense. Okay, for one: I'm hearing the vocals a little muffled by the music, it sounds.
Maybe give it some air and breath boost (4k-6k) 2 - 3 dB. See if that helps at all.
 
LOL I think the best way is to mute them. There's only so much one can do with terrible phrasing, performance and intonation. They definitely don't deserve to be this present in this mix, lower them a lot. Try some effects/panning to hide them some more.