If you really don't feel they're better enough to justify the price that's fine. Find some cheaper cans that sound better than your ibuds and save your wallet. If you want something that will really give you that "secluded" feel, try iem's.
Spotify Premium does. Free is 160kbps OGG........good luck telling the difference between 160kbps OGG and FLAC, i can't, and i've tried. Heck, i can't even hardly tell 128kbps OGG from FLAC, only with some tracks.
Not in closed. SRH440 is probably the best of the bunch you mentioned, but it's hard to beat the HD280 pro's isolation, they also have better bass than the SRH440's. I really know nothing about the CAL so i can't comment on it.