Folding military style camp beds are very usefull and take little space when folded.
Ample supplies of sheets and blankets are essiential, if money is tight these may be obtained from charity shops.
Budget priced new linens can be obtained in bulk from hotel suppliers.
New and issued blankets, and sometimes sheets can be obtained from government surplus dealers.
Hotels normally replace linens before they are worn out, laundered ex-hotel linesns can be purchased very cheaply if you know where to look. (I can recomend a supplier in London, though most members here are from the USA)
Pillows should be replaced regularly for best comfort, store the old ones for emergencies.
Stock up on cheap pajamas and bathrobes, from discount stores or fleabay, those who dont normally bother with such may want them in crowded conditions.

Plan for blackouts as these often occur with other ermergencies.
Oil lamps and candles are cheap and simple but a potential fire risk, and the risk is increased by a crowd who may be unused to the risks of flame based lighting.
A generator or a central battery standby lighting system would be best.
If reliance must be placed on lamps and candles, then plan ahead and install in each room a wall bracket at high level, from which an oil lamp may be hung, much safer than placing on a table where it might be knocked.
If the ceiling height permits, also consider hooks in the ceiling from which oil lanterns may be hung., well out reach of children and pets.

Buy a good stock of basic flashlights, at least one per head and plenty of batteries.
Buy several cheap battery radios, preferably with headphones.

Ensure plentiful supplies of T.P. and cleaning products.

Keep a large supply of non perishable readily prepared food.

In a larger home, consider a secure store room for anything valuable or dangerous (firearms, bulk liquor, medicines, dangerous tools, household chemicals, poisions etc)
In a smaller home, lockable steel office filling cabinets are handy and very cheap.

Carefully inspect your home for hazards that you have grown used to and avoid, but that could endanger others.
Damaged electrical outlets or lighting fixtures, worn carpets, slippery floors esp in/near a bath or shower, etc.