Merging objects/layers in Illustrator into a single Object
I just want my artwork as a single layer/object, so I can easily scale it in size and adjust its colors--preserving the perks of having it vectorized without the hassle of having to adjust the color of several different fills and strokes.
I have a single layer, but within it there are four objects (or sub-layers--sorry, I am not familiar with the proper terminology).
For whatever reason, I cannot "expand" it into a single object using the pathfinder panel. Nor can I merge all the objects within my layer together using the down arrow on the layers panel and selecting "Merge Selected".
You need to GROUP all of the objects inside that layer so that when you click on whatever object, they are all selected. Simply select all your objects and press Ctrl+G.
You mentioned fills and strokes, take into consideration that if you have strokes in the group, by default, when resizing, the strokes maintain the same weight and don't scale proportionally. To resize the strokes proportionally you can either Expand Appearance (this won't allow you to further edit the stroke AS a stroke, it will convert it to a surface with a fill) or go to General prefs. and check Scale Strokes & Effects.