Hi
Q1. There is an RTS beta which has some utilities for helping with this. See also RTS game pathfinding Currently they would definitely mess with the other enemies.
Q2. Yes. You can adjust the priority. The agents always move away with at most their max speed however. I think the above mentioned RTS beta also has some minor tweaks to improve the behavior, but I’m not 100% sure.
Q3. It’s not that good I have to admit. There is support for it for the RichAI movement script on recast/navmesh graphs, but it is unfortunately the part of the system I am the least happy with.