Well, as obscure as this might seem, I actually think the opening to Progress sounds a ton like Prologue from A Song For XX.
And I'm sure I'm not the only one to think Walk sounds similar to Ivy. And I think Zutto... and Carols have a similar sound to them... In terms of progression and the higher pitched vocals in the chorus.
Last but not least, I think Missing actually sounds like something from A Song for XX or around that era. Mostly the verses. I also can hear the slightest similarity to Free & Easy, but more aggressive (?)...