I would expect iLife '06 to be released at MacWorld SF in January. This has been what has happened in the last two years and I wouldn't expect it to be any different. New Macs from then will start shipping with it and there will be an up-to-date scheme for those that don't from that date.
As for Core-Image versions of iLife - I don't really understand the fuss about it. iPhoto 5 effectively uses its own coding of core image to produce the editing effects and so an update would theoretically just kill some of the repetition of code in this respect. Maybe a point update already did that for Tiger users.
However, don't forget that the iApps are generally targeted at consumers, not pros, and these are people who are likely to have iBooks and eMacs and Mac minis, all of which don't support Core Image. So they must be careful not to allow performance to crawl for these machines when updating. (For example, Dashboard crawls on my brother's iBook 1.2GHz, even though it's a full year newer than my PB). My 12" rev B PowerBook does cope with Core Image, but only just as I only have 32MB of VRAM and the old nVidia 5200 GO. I wouldn't want them to be too reliant on it.