/ pretrialpause = replace(100-2000)
is not not really valid syntax in this context -- i.e. it will not sample from the range 100 to 2000, as I suspect you intend it to. Instead the above will evaluate 100-2000 as a mathematical expression, yielding -1900 as result, and then take that as the pretrialpause. Since a pretrialpause can be no shorter than 0 ms, you see none at all.
/ pretrialpause = replace(100, 500, 1000, 1500, 2000)
on the other hand would be valid syntax in this context, and you would see jittering.
That said, to sample from the full range 100 to 2000 at random for the pretrialpause, you'll want to do something like this:
/ randomjitter = round(rand(100,2000))
/ randompretrialpause = 0
/ ontrialbegin = [values.randompretrialpause = expressions.randomjitter;]
/ pretrialpause = values.randompretrialpause
/ stimulustimes = [1=ball3, blank2, blank1; 100=blank3, ball1to3e; 200=blank1to3e; 220=ball1to3d; 320=blank1to3d; 340=ball1to3c; 440=blank1to3c; 460=ball1to3b; 560=blank1to3b; 580=ball1to3a; 680=blank1to3a; 700=ball1]
/ validresponse = (noresponse)
/ timeout = 800
/ branch = [if (counter.inclusionplayer1.selectedvalue == 2) trial.player2turninclusion1to2]
/ branch = [if (counter.inclusionplayer1.selectedvalue == 3) trial.yourturninclusion1to3]
Hope this helps.