Getting started. Looking for which apps to use and how to create workflows.

My background is video editing, web & database design. I am moving in the app development direction right now. I have the creative cloud subscription and use photoshop often enough as well as a few others. I started learning blender last year and will likely begin with that as my 3d mesh editor. I have a basic game idea that I have simplified down to start with after spending several months researching how to get started. Was looking at the HUD systems today and I am excited to get started. I have a few getting started questions…

As well, I can’t quite figure out how to align objects in the editor just yet. I switched to top view, but … still couldn’t figure out how to do what I wanted, just line up a wall to match the edge of another. Are there any tricks to this? I tried adjusting the snapping and a few other things but couldn’t quite get the effect I wanted. With snapping off I can get them close, but was just curious how this could be done more efficiently. I am wondering if the mesh tool may help here.

Duplicating Content:
I am learning how to use Ctrl-W to duplicate a mesh that is placed on the level. I noticed that it offsets the mesh just slightly. Are there other ways to duplicate objects? ( such as in photoshop, holding alt while dragging ).

Asset management:
I am learning how to import things into the project, such as the starter content for mobile apps. What happens to unused assets when you publish the app?