Heh! Sorry, not really sure how I ended up writing them out of order. I edited my post to correct the order.
2. You don't necessarily need to use Lua script. I believe it's possible to link to a called by other action block on chasing character collision with character being chased? You set a random value inside of said action block then you would query if value is x, y or z (x, y or z being a number between the min & max value you specified in the random value) which you would then use to trigger some other actions based on the returned result.
basically... (action parts)
set random value 'value_name' between 1 and 5
if value 'value_name' == 1
-- insert some actions to perform here
end if
if value 'value_name' == 2
-- insert some actions to perform here
end if
if value 'value_name' == 3
-- insert some actions to perform here
end if
if value 'value_name' == 4
-- insert some actions to perform here
end if
if value 'value_name' == 5
-- insert some actions to perform here
end ifThat's the general gist of it without me going into too much detail
5. it's complicated & even more so if both characters are moving around because that requires loops to constantly calculate all characters positions & whether any characters radius are overlapping. Also it's not possible to affect the way system/borders in any way with Lua script as far as I'm aware. It's already complicated enough to have a character stop & perform an action without having to come up with some calculation to divert the characters walk path around the other character. Most simplest solution would be to have the npc stop when they come into contact with your radius & then listen out for when it's no longer colliding with your character & then have it resume its journey to wherever it was heading prior, but even that requires a fair amount of work.