I hope im not too late in this discussion. My family is huge and when someone gets married (at home in a catholic church) everyone gets together and help out in someway. Largely they help out with the reception. When my aunt got married, after the wedding everyone went to the church's hall and ate and danced. The food was catered by the family and served buffet style (it was yummy of course because it was "Family" cooking). There was a cake cutting, people danced and everyone went home.
Since your family and FI family was influential in your decision to cancel the DW, I would certainly hope that they would be willing to throw the reception for you in lieu of showers, brunches, and other stuff.
What do you think?