I'm trying to think of a reason that v-belt slippage could save something from breaking.
Nothing obvious - other than a backfire - comes to mind and the only thing breaking there could be the belt.

If something gets into the fan, you've got problems no matter what style drive belt you're using.

The cog belt looks like an excellent way to go, especially in view of the limited amount of 'wrap' around the water pump pulley.
I run a single v-belt with about that same amount of wrap and it slips once in a while.
A newer setup with dual v-belts is expected to prevent the occasional slip bit.

A serpentine belt is something to consider as well.
There's a lot of friction with one of them and would probably be easier as well as cheaper to set up.