Hutch sizes and being left on own at end of a garden
Feeding: just eat carrots and lettuce, muesli, no need for hay and cleaning/changing regulary
Easy to look after (ie: ignore, give carrot & lettuce now and again and stick at end of garden with no enrichment, running time, or social interaction and toys)
Need to live outdoors (& no understanding of the need to fox proof)
Medical stuff.. not needing to vaccinate, neuter or have regular health checks for dentals, etc
ETA: makes for 6, but yes, allergic to rabbit... are you sure it's not just hay allergy????