I was stuck working with two 256 View editors, one would not preserve or set the origin point and the other would screw up the palette by making all black colours white. I assume your editors don't have these problems? 
I hope not! haha...
Is it also possible to match an imported background's palette to a pre-existing SCI palette instead of creating a new one? How does it currently work? Do the imported backgrounds automatically set aside the first 64 colours in the palette for sprites and simply use the remaining 192 only? That's how Sierra's backgrounds worked. Otherwise sprites will look wrong in-game.
Yes, matching the current palette is actually much easier (that functionality is built into windows). That's what I started with, and the results were generally terrible, so I thought it was necessary to create a palette from the image colors. I found some color quantization code on the web and integrated it into the program.
Right now it looks at which colors are "empty" in the global palette and uses those slots only (hence the view of Roger Wilco still looking ok in the image above). And yeah, like you said, the first 64 colors (and last color always white) are generally set in the global palette, leaving 191 free to use in the pics.
I'll likely offer a choice of options when pasting in an image:
- use only slots that are "unused" in the global palette (or any other palette of your choice)
- conform to an existing palette
-

not sure what else would be useful
Does/will this also have the ability to compile SCI1/1.1 scripts or no? I'm thinking no...
Not currently. SCI1 scripts are quite similar to SCI0 though (in fact, nearly identical), so it shouldn't be too much additional work (though surprisingly, at least one of the opcodes changed behavior). I still need to implement writing to the resource map for SCI1 though - the format changed slightly (though not as much as SCI1.1). Also, unless I created an entire template game for SCI1, I'd to support generating .sco files from compiled scripts - haven't looked into this yet. I'll think about this...
Note that the terms SCI1.0/SCI1.1 aren't very exact. The code, the resources, the resource map.... they can all be from one version or the other. For instance SQ1-VGA and SQ4 are both listed as SCI1 games. But SQ4 uses the SCI0 resource map format, and SQ1-VGA uses a slightly newer version.
Are there any "SCI1.1" improvements over "SCI1.0" that you consider important? It seems like most of the changes had to do with conserving heap memory (e.g. splitting script files into separate script and heap resources). Using the SQ4 or KQ5 interpreter would probably be the least effort... they use the same resource.map format as SCI0.