Will this fit inside one of the slots on the Swiss Army Climber 2? I want to replace ether the tweesers, or the toothpick with this pen.

No, this is a dedicated slot for the pens diameter and length.

I have a 111mm Workchamp. Will this fit that?

I don't believe that the workchamp has a dedicated ball point pen slot. This will not fit in a slot meant for a toothpick or tweezer.

does this fit the "cybertool" knife?

Sorry. Not familiar with that knife.

Will this fit a climber Swiss Army knife?

With rare exception, it does not. The Large Ballpoint Pen only fits in a special slot featured on the 'Plus' scales, on the same side as the Toothpick (it does not fit in the Tweezers slot). The Climber does not have a pen slot in its original configuration, though the Plus scales are sometimes added by enthusiasts.