Convert built in fridge into cupboards

Both options are possible

Hi there this can be done but you might have remove doors of built in fridge freezer and then if the doors have not got hinge pockets you may need to cut these it to except hinges to fit like a door , if you handy with tools you could try supplier to see if they could get new doors if tge kitchen is still sold . Hope this helps you

If by mini you mean under counter F/F this wouldn't have a unit, instead it will be just a gap between units. The gap will be the size of a unit and can easily be fitted in place of a under counter F/F. The existing door will be okay to re use but might need drilling to suit the hinge locations. Some F/F use a fixed hinge design and have no use for hinges and then would need drilling.