Stoner, my dad was a refridgeration engineer, so I grew up with it.
The ideal thing would be the kit out of an old commercial fridge freezer as they are configured for blown air.
The pressure in a fridge/freezer is NOT dangerous. I have seen hundreds of systems punctured and pipes cut off systems and its no worse than letting down a road bike tyre (or Fox Shock!).
Compressors have a fill pipe. This is normally braized close at the factory, so if you want to refil then you firstly have to fit a fill valve.
The heat exchanger on the back of the fridge is low pressure and is relatively easy on most to take off, braize on extensions and relocate.
Most donor fridge freezers have the internal heat exchanger (the bit that gets cold) integral to the shell of the cabinet, so you might struggle to find an internal heat exchanger.
Hope this helps!
IF it was me then I would buy a 300 quid air conditioning unit instead.