1. ?There are a few approaches that can be used to develop a Work Breakdown Structure (PMBOK, 2017). Using Guidelines

1.  There are a few approaches that can be used to develop a Work Breakdown Structure (PMBOK, 2017).
Using Guidelines: Past projects can be used as templates to create a WBS for the current project. There could be other documentation created for this specific project that could be used to create the WBS. Essentially, guidelines are a method in which project-specific documentation and resources are used to create the WBS for the current project.

Top-Down: This approach allows the project manager to start with the larger aspects of the project to break them down into smaller components that can be easily managed.

Bottom-Up: This approach is the opposite of the top-down approach, in that the project manager can start with team members, small tasks, and activities. Afterward, larger categories and groups can be created until you are found with a completed project.

2.  I prefer theTtopdown Approach liking the top-level review first, and then having the creation of items and tasks required. Do you prefer one level over the other?  Do you anticipate using the Analogy approach is a factor?

"Analogy Approach – This involves review and analysis of the WBS of similar projects previously executed, to customize and adjust to the needs of the current project. This approach accelerates WBS creation," (Lewinson, 2012).”

3. The deliverable-based approach is something I've always used as so much of the software industry is centered on building a product.  (thus, the "deliverable").  From there, the top-down approach has been a staple of almost every project shop I've been in.  It might be, and probably is different for other industries, but beginning with the big stuff and working your way down to the task level is 100% the easiest way to approach building a WBS.

Regarding the analogy approach, I think that's where we get into developing templates (whether for the WBS itself or for project plan skeletons).  We both are now several classes into the PM program, and historical performance data has popped up in each class thus far.  In terms of applying it to the WBS, historical data use can really shorten the WBS build process if the work is similar enough from one project to the next.  Still, it's not a bad idea to have a WBS skeleton (format) as a general source.  That keeps builds and documentation aligned across many projects.

As you've mentioned above, I can get benefits from combining the analogy approach (even if time is not a factor) and the top-down approach, because it may add continuity across the projects where appropriate.

4.  There are many ways to develop a Work Breakdown structure. The three commonly used I have selected are as follows:

The Top-Down Approach – this is one of the most well-known methods commonly used. During this approach, you identify the most significant or largest task in the project and break down from there.

The Bottom-Up Approach – another common method used, but instead of starting with the most complicated task, you start with the easiest task and complete it first. This is an excellent method for brainstorming a solution to the problem (Mukund, 2017).

Guidelines – this is one of my favorite approaches, because it sets the guild lines for how to create the WBS and makes planning each part easier.