Hhm, it's hard to say what's going wrong, without knowing the exact steps you took. Some of the problems sound like they could be related to selecting the wrong object. When you have 2 or more objects which are identical in shape, or nearly so, stacked up on top of each other, you'll want to be sure to use all your clues for knowing which object(s) is(are) selected. For example with a button where you want to simulate some depth, you might have a base object, and couple of partially transparent objects, for shading and/or highlighting on top, and maybe even a cast shadow below. Clues can be found in the status bar, for one. It gives different info depending on which tool is engaged. The selection tool always gives the type of object, and the other tools vary as to what the status bar says. You can also use the indicators in the bottom left corner of the window. There is shown fill and stroke, as well as layer and opacity. For example, if you're trying to select a gradient, you can see that in the fill info, when it's selected. And I know this is going to sound simplistic, but sometimes I even count my clicks if I'm using Alt + click to select objects in a stack.
You can make sure that the gradient moves with the object by clicking "Move gradients along with the object" button on Selection tool control bar.
Yes, any offset path can be moved independantly, so grouping is not a bad idea.
When you say you need to edit the offset, do you mean node edit? If you previously used Dynamic Offset, you'll need to use Object to Path on it, to make it editable as a path. But if you mean you need to edit as an offset, you won't need to do anything else. If you're just using regular Inset/Outset, it's not an issue.
As far as selecting the offset, there's no reason you shouldn't be able to select it....unless you made it transparent. You can select using either the Selection tool or Node tool.
With Linked Offset, it automatically creates a duplicate path for you. But with Dynamic Offset (and regular Inset or Outset), you have to remember to duplicate the path/object yourself, and then apply the Dynamic Offset to that duplicate.
I hope this has been at least somewhat helpful. As I said, it's hard to know exactly what's happening, without know the exact steps you were taking. If you still have trouble, be sure and notice exactly what steps are needed to recreate the problem.
