For the secondary weapon preference in Left 4 Dead 2, Bots will usually prefer two Survivors using Magnums (Nick and Rochelle) and two Survivors using dual-wielding Pistols (Coach and Ellis).

Francis and Louis however, are not over their right successors as Louis goes over Ellis and Francis over Coach.

This is likely an oversight, as the Left 4 Dead Survivors gain the weapon preference of the Left 4 Dead 2 character's slot they fill on the character selection screen.

While Bill keeps his Assault Rifle variants, Zoey is now with Assault Rifles as well, Louis takes over Francis' role as the Auto Shotgun variants user, and Francis is now the team sniper with his preference for Hunting Rifle variants.

In the Left 4 Dead 2 ports of the original campaigns, the original Survivors have different preferences.

Zoey and Ellis prefer sniper rifles, Francis and Coach prefer automatic shotguns, while Bill, Louis, Nick and Rochelle prefer assault rifles.

The primary weapon preference as Survivor Bots are always the same for every Survivors.

The major gameplay difference between the Survivors are the weapon preference as bots, and the 'Hit Box'.

Left 4 dead 2 ports