Set up a table for food and drinks, and use paper plates and cutlery to save time on cleaning.
Candles set the mood for a housewarming party, so maybe a centerpiece like this will be great!!
(pic credit: digsdigs.com)
Have chairs around to encourage people to sit while eating.
Suggested Menu:
To minimize mess, it's better to use food that can be held easily, or if it's wrapped separately.
Sandwiches
Satay/ meat skewers
Dips
Buns
Cookies
Mini pizzas
Samosas