If the exterior walls (red) are expanded and the interior walls (blue) are stroked paths you will not be able to get the kind of snapping you are wanting.
If both exterior and interior wall paths are expanded you can go to View> Snap to Point and then grab the path you want to move by the corner you want to join and it will snap to the other path corner ...
You don't need a script to do this.
You could record an Action, and assign it to a function key, then increase the black by 10% using Edit > Edit Colors > Adjust Colour balance. Then record a similar second Action assigned to another function key, but this time to decrease the black by -10%.
Here are two such Actions I recorded. One named &...
A brute force solution.
Have a corner adapter with new anchor points inserted to the right places:
In this case the stroke widths are 2,5 mm and 5 mm. The green adapter is a 5 x 5 mm strokeless square which has got two times Object > Path > Add anchor points.
The exact placement of the adapted is based on its centerpoint, so centerpoints should not be ...
Yes it's possible in Illustrator. Select both cherries and do Object > Compound Path > Make.
When you export to SVG, both cheries will be one single path.
<?xml version="1.0" encoding="utf-8"?>
<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://...
File > Export Selection might be useful for what you want.
There's no need to hide any layers, just make sure everything you want to export is grouped. If you want to export a background as well, you will need to use a filled rectangle, and also group that with each object. Using Export Selection ensures that the export is based on the selection only, ...