What kind of problems do you plan to encounter, possibly high step-ups to clear rocks or fallen trees? If so, you will have to lift up on the bike and possibly turn the walk mode off briefly while doing so.
Good point. I've never thought of what you describe. I would think as long as you don't remove your hand(s) from the handle bar, you wouldn't have a problem in the walk mode but that's strictly a guess on my thinking.
Keep one hand on the left brake lever and the other on the walk assist. If the bike should lurch forward, it will pull on the brake and shut the motor off. I use mine occasionally to "walk" the bike up stairs.
No. Walk mode is a separate mode where you can walk beside the bike and it'll trot along at 4-6km/hr. You usually need to hold a button while walking the bike and not all bikes have a walk mode (I have a NCM bike not an Lectric).
Fun tip: When I had to ride my bike beside someone walking I was able to ride the bike in walk mode and keep pace easily.