I got a small cast iron grill. I store a few bags of charcoal. Now before folks get up in arms about fumes and smothering to death, It will be used in the bathroom and a battery operated exhaust fan will remove fumes to the rooftop. Since we will only be heating up soup type meals, no people gathering smells will be exiting. Yes, the bathroom is not the most deletable location but if you have kept is clean, it not going to be a health hazard.
Water is the next issue, Bathtub Bob (100 gallons or the 65 gallon version). Hot water heater (30 to 50 gallons) Bottled water another 30 to 40 gallons (remember folks - apartment). Water is going to be a real problem for your family -- 5 people = minimum of 5 gallons per day. More likely 7.5 gallons per day. With the absolute best scenario, you are looking at about a month worth of water. So you are going to have a dire problem very quickly. You are going to need a water purification system in place before the SHTF. You will have to scrounge water from unbelievable sources. Golf course water hazards, full of germs and duck crap, will look like a desert oasis.
Now to defense. Black plastic garbage bags taped to all windows -- prevent light from showing or movement from within. Pre-cut plywood inside window covers (not installed -- apt.manage gets real upset if installed) that can be nailed or screwed if you have a battery powered drill, slow down intruders. keep hammer and nails handy, for remounting window covers that have been knocked in. You and wife will have to be armed and prepared to repel all boarder, at different windows. It will most likely be more than just one invader if they are trying to kick in your window or doors.
Now this is going to sound real harsh, but you cannot take any prisoners and if possible, you should hunt down any that have attacked your apartment. Now my reasoning is that if you have done a good job of repelling these folks and they figure they are not going to get your supplies, then they may decide to just burn you out. You cannot defend against a fire attack. Jm2C