Alignment questions

[micheus]

That's too much questions and prepare a shape similar to these you shown requires time (that I don't have much). So, I'm going to answer one by post (I'm not sure when I will end to answer you )

But, in the mean time you may want to review your project observing something that I already told you in your first post (tips). I think you didn't pay attention to it because of this comment:

So far, I can "flatten" a group of vertexes along X, Y, and Z axis. I can't figure out how to "flatten" along an axis defined by two end vertexes. This would also be helpful to constrain subsequent inner vertexes to a standard plane.

By reading that you would have noticed that for every command on the context menus you may find up to three options that you select by chosen it using each mouse button (RMB, MMB and LMB) and that information is on Information line and floating Tooltips.
You also can input precise values by hitting [TAB] during a command action.

On Wings3D you don't have manipulators - you must to define axis by using face's normal, edges (and you can pick edge's normal too) or vertices.

Let's go...

1. GROUPED PART ALIGNMENT: Question #1: How do I align this part?

There is no direct way to make that movement. Absolute Command->Snap [RMB] works in some case, but not in this one.
I believe you would have simplified your process if you (even moving as you did) have put the "part1" on its final location.



I believe you will need to move some vertices along the edges. You can use Move [RMB] and pick the edge as axis or you can enable Tweak mode and use the Slide command that works for vertices and edges. The native Slide is available only in Edge mode [E].

Another tip: keep the Selection Group Window active. Work with temporary selections is very easy if using it.

I suggest you to take a look at Wings3D Channel at YouTube. There are some tutorials that may help you to understand better some of Wings3D commands.