I think I found a solution to the gate issue!!! I am copying and pasting this, as written, from the original source...
However, after enabling testingcheats, and while in Build/Buy mode, and by holding CTRL+Shift and left-clicking on the gate, the option for 'Lock' was available. So I selected that. I also selected 'enable for triggers' or something similar, and then activated that, I was able to set the gate as 'front gate' in Live Mode. From there I could designate who could pass through the gate.
This worked for me!
Something else I noticed: If the gate is not on a closed fence (ie a box or the gate touching the house on both ends) it won't allow you to lock it!