First of all, why are you creating two armatures, instead of a single armature with two bones? The latter sounds to me, given the “connection” that you mention, like what you want…
Otherwise, so far, so good, I think.
In each sphere’s armature modifier, there should be a field asking for an armature name, labelled “Ob”; copy the name of the relevant armature for that sphere and paste it into the armature field of the modifier.
This shouldn’t be called for, I don’t believe, given the approach that I find works with Chicken.
I believe so, yes; you might as well disable the “Envelopes” option in both the modifier and the armature itself, so that you don’t accidentally end up with some degree of envelope transformation that isn’t carried over.
If you mean the field in the modifier labelled “VGroup”, then I think that you can just leave this blank for now.
Instead, set your armature into “Pose Mode”, select a sphere, and enter “Weight Paint” mode (in both cases these can be found in the little list that should be found beside the “Object” menu in a 3D view).
In “Weight Paint” mode you basically tell Blender to what degree each vertex is affected by each bone by first selecting a bone, then “painting” the relevant vertices to indicate the degree of effect.
I recommend taking a look here for more information, specifically in the sections “Connection between Armature and Mesh” and “Vertex Groups & Weight Paint”. It appears to refer to an older version of Blender than the one that I use, based on the items shown (and not shown), but it also appears to remain informative.