My picture is based on a traditional Russian church with ornate pillars.
1.b.i. Each of the 3 pillars is a group. ii. I created each pillar on a separate layer. After each pillar was complete, I grouped all of the pillar elements together so that I could easily move each pillar around in relationship to the other pillars until I found a look I liked.
2.h.i. I moved the three pillars layers around a bit until I decided to make the blue pillar most forward. The gold pillar was definitely going to be in the back, but I went back and forth between whether the green or blue pillar should be forward. I picked the blue because I liked the subtle difference with having that pillar in front.
1.a. If you are going to use a single layer for a complex graphic, I recommend grouping like elements, or grouping pieces of a larger element (e.g. items on a face: nose, mouth, eyes, etc.). One pitfall of a single layer is that making adjustments later can be a challenge.
1.b. I think I will take advantage of layers more.
1.c. I have decided that I don't really like using the Merge shape setting. I like to use the Object setting for just about everything and then if needed, I modify and merge items later. Using the Object shape setting provides me the flexibility I want to change my mind and make adjustments.