LFE channel is coming along; the major decisions are made, so it's mostly just tweaking the details now.
I've got the five channel upmix from Satanika, and I spent a while going through it to see if there was anything that needed adjustment. I found a rather distracting phase error early in the movie that will definitely need to be corrected: this was introduced by one of my edits and was probably unavoidable due to the impossibility of completely matching the different recordings to each other at that point. After much trial and error, I'd made the EQ as close as I could, but the differences in dynamics and frequency response between them were such that a more exact match could not be obtained. In stereo it sounds okay, but evidently the upmixer was confused by the difference and choked on it.
At first I despaired of being able to do anything to correct this, but eventually I had the thought of upmixing the two recordings separately and then editing them together afterwards, which would bypass the problem completely. (Fortunately, none of my other edits exhibit anything like this, so it only has to be done once.) In addition, I'd like to manually pan a few things out of the center channel, since upmixing tends to make the mix too centrally focused in places where the signal is strongest, causing some occasional brief clipping, as well as not being quite faithful to the original which would have sounded wider in those places.
I'm also comparing the phase relationships of the channels to each other. It turns out the upmix did not invert the relative polarity of the surround channels, so I'm going to do that myself. Which surround channel is inverted will depend on their coherence with the front, and how the combined bass frequencies sent to a subwoofer would interact with each other.
All of these tweaks I'm making will clear up some little nagging problems that existed in the previous version, which at the time I was not able to fix properly. Once it's done, I'll encode an AC3 as well as uploading the edited lossless files, so that they can be used for HD projects.