1) 2 hostile buildings might be close to each other (distance) but there is either only a very long path or not even a path available
between them. If reachability is not checked, they count as "near border" but they can not attack anything so thats not really true...
by enabling this option those buildings then may count as "inland" thus drain no soldiers.
2) There are 3 settings if I remember that right, one makes generals quite strong (1 general kills 11 privates I think), s2 settings
makes them quite s2 like ( 1 general kills 7 privates) and weak settings then result in weak generals (1 general kills 3 privates).
This mainly changes what rng is used when deciding if a soldier gets hit by an other soldier / hits another soldier.
3) You can set a priority for building sites. Without that addon you may place: Sawmill, woodcutter, woodcutter, forester - now those
buildings are built in order (or should at least). When enabling build sequence you may set woodcutters at the highest priority, which
then results (placing same order) in: woodcutter, woodcutter, sawmill, forester