Thanks, that's helpful.
To clarify, the reason I was planning on moving these arborvitae is because I lost a tree in another spot, and that tree was providing some privacy. So my idea was move a few arborvitae to that location to establish a privacy screen.
Per your info, I'll abandon the plan to move any of these arborvitae.
As for selecting new arborvitae, I was thinking 6ft because that would get me closer to having an effective privacy screen (would need 7-8ft) than say a 4ft, which would take 2-3 years to even get to 6ft. Your thoughts?
In terms of replenishing soil, I've got plenty of compost (we compost food waste such as eggshells, banana peels, etc.). Anything else that would be helpful, especially for the area where I lost a 25ft pine tree and will be planting new arborvitae?