Chris is still on Imagem Music official page and I doubt the situation could change again so fast:
Here are my thoughts about Chris's relations with record labels / publishers, based on what I know (you wrote almost everything I know about it right).
Chris was apparently disappointed with his comeback to cooperation with Warner after he signed to Rhino UK, a member of Warner group. I guess he simply had to stop resisting and sign again to a major label either just to improve his financial situation caused by sticking on to his own independent label and recent unpopular blues-oriented albums, or he also wanted to get in closer touch with Warner again to regain rights for his back catalogue (La Passione master tapes first of all I think).
This way or the other, it apparently did not work as he wanted it to, since it is clear that Warner is no longer much interested in using or sharing their rights for the pre-2002 Chris's records. In 12 years they only have released several dull compilations (Heartbeats, The Works, etc.) Not a single sign of intention to release reissues with bonuses or B-sides compilation or any old live material. Yes I do agree this is really very strange and really is a shame.
I suspect one of the main reason for this is that Chris split up with Warner in 2001 with a scandal, and Warner became even more angry after they had refused to release Stony Road and then it suddenly went gold in UK, being released on the independent label (Edel / Jazzee Blue). Thus I think their relationship with Chris is still very hard and signing for Rhino in 2009 did not improve that.
I also assume one of the main reasons of systematical postponing of the new La Passione release is the major problem with Warner regarding the copyrights.
I was a bit surprised when I learnt that Chris signed to Imagem right after Santo Spirito release in Sep 2011, but I am sure this is a positive change and wise decision.
By the way, Imagem is most likely supposed to publish Chris's post-2002 records in UK and Europe except for Germany where Chris is still represented by Edel Records / Ear Music which have released 2008 compilation on vinyl recently.
All in all, i really do hope the situation will change for the better in the end and we would see some really interesting new releases and reissues.
Thanks a lot to anyone who read and commented on this,