Excellent questions.
The RVO controller is what unity pro users use to move around with local avoidance. Every movement script (move to, follow path, etc) first checks if you've got either a character controller component or an RVO controller component on your actor(the gameobject that moves). If you don't it creates default ones according to your license.
The additional script package includes a dummy rvo component. This makes unity think it has such a component and therefore it won't give you an error. The advantage this is giving us is that we can use the same core package for both pro and free users.
The warnings should not be there though. Can you quote one? Maybe it's something that's easy to fix.
Is your actor noticably above ground? Do the examples work properly? Do you have a collider on your ground? Does your actor have a character controller (at least while the game's running it should have one, but maybe this is the same problem as the RVO controller warnings).
Select your A* gameObject in the scene. It should by default show you the graph, and unwalkable nodes should be red blocks.
Paths are only visible if you have the actor's FSM open and if you can see the action that moves it. This is a bug I've yet to crack
To calculate a path you always get the nearest node to your gameObject. I can implement it so the final waypoint is exactly your gameOBject , but that won't do any pathfinding from your last node in the path to your gameOBject, so it'd be asthetics only.
What do you mean by give it and store for path info? Which actions are we talking about? The path output usually is an FsmObject of the type FsmPathfinding/FsmPath.
To update many nodes at once, use the "update graph" action. To make the nodes walkable again, remove or disable the collider of your building and use another "update graph"