Aerocool makes some 140x20mm fans. IDK why no one seems to do slim 120mm fans.
It might be possible to use an Arctic Cooling 120, but I can't see how the fan mounts into that bracket thing so IDK if you could recess that up into that bracket a bit with some type of spacers for mounting...
I can't really get a mental picture of which fan you need - the one in that side bracket, the one on the Freezer or where - and exactly where the clearance problem is?
.bh.