Lets get rid of the 3 sided rubbish and dispense with the Gauls and the Zulus (most fights generally only have 2 sides !!!)
Firstly is the troll even vaguely intelligent and would it use the pots of cottage cheese rather than the crossbow (as we all know Jane is highly allergic to cheese - even when drunk and due to her size is pretty invulnerable to all but the highest powered crossbows.
If we assume with the meagre intelligence of the troll that it picks up the crossbow rather than the cottage cheese we have an interesting match on our hands.
Jane will posture, swear and stagger at the troll (yes that's right in Warhammer trolls do have a slightly higher initiative than JAne) and thus the troll will get its shot in . Assuming the crossbow is of average c.80lbs draw - power then unless it luckily spawns a head shot, Jane will only be minorly wounded. Thus sorely aggreived will run in screaming wielding the chainsaw. The troll would then have to pass a fear test , but assuming it made it would take several serious but non fatal slashes from the chainsaw. Assuming that JAne is drunk it is only a matter of time before she cuts through the lead and electrocutes herself.
Then the troll will regenerate. The fight is likely to be long messy and bloody. Sadly it won't go in Janes favour unless she persuades the troll to do some RE coursework using the pencils and then twats it when she is sober.
I don't really think the zombies are relevant in this fight?