Kylie + Garibay and Kylie Christmas are Firewheel releases (essentially a Darenote, but not Darenote, company) licensed to Parlophone, as are some stray songs released around this era like "Wheels on Fire". She was out of contract but Parlophone were happy to distribute the releases, possibly to keep her sweet, reap the "Santa Baby" placements, and continue their professional connection to her without the negativity of Kylie Leaves Parlophone press - remember that it was big news when Kylie and PWL parted ways, and when she left DeConstruction, that company folded within about a week. For Kylie, it was likely just a handy way of being able to put product out while looking for a new label.
Kylie now releases her music as Darenote licensed to BMG Rights Management, where Darenote, her company acts on her behalf and BMG acts as a label services provider (marketing, distribution etc). The joint release between BMG and Parlo for Step Back in Time essentially is just a way to get all the material together cooperatively for mutual benefit, rather than your standard three-year deal where the present label takes all the risk while the older label gets to sit back and count the fee income. It also reduced the risk of Warner Music releasing their own Parlophone-era greatest hits and diluting the market, like how Sony/BMG did with all those endless repackages of the DeCon albums, or Uncle Pete's awful 2002 PWL Greatest Hits album.
