My Household... How many do I prep for?

This sounds simple, but in my case, it's not so simple.

I'm married to a wonderful woman who comes from China and works half her time in Asia as part of her job.  That means that last year...

For half the time, I was in the house alone

For half the time, there were two of us here.

But...

For one month (well, 5 weeks), her family was visiting and there were 6 or 7 adults in the home.

Do I prep for one?  Six?  Take the average of 2.33?

I'm thinking I base most of my guesswork on 2 people.  I'd hate to have to have the conversation of "honey, I wasn't expecting this would happen while you were home".  I'm not sure that would go well.  

Yes, there's a non-zero chance that adversity could fall us with a house full of guests.  But I think in that case, I'd scramble to find an alternate... maybe we send them home early, perhaps a long sight-seeing tour of the west coast if that proved to be an option, or something like that.  

(I remember a friend's youth group that was on the ground in Haiti when the earthquake hit.  They wanted to stay and help, but their hosts really wanted to get them to safety so he could concentrate on helping the locals... I guess would apply in my case as well.)

So... assume two people... plan for a larger possibility for a short time.

But there's more...

What if people I know and love come here for help during a time of adversity?  I'm not suggesting my goal is to feed multitudes in this, but I live in a cul-de-sac and happen to like my neighbors.  I couldn't sit around and be well-fed watching the children next door go hungry.  

So that's one reason we might want to lay in a little extra.  There are others.

FEMA says each household should keep 2 weeks worth of food and water on hand.  If every household did this, I wouldn't need to worry beyond my own household.  I know they don't (I have not until now).  

And... I also don't completely trust FEMA.  The present administration has clearly demonstrated to me that government CAN be incompetent.  I need to plan for that.  Don't get me wrong... our society (including the government) is filled with competent caring people, but I'd like to have enough to last me so I don't have to go to the SuperDome, but move to the secondary phase once things settle down.