I remember once starting a thread about this. Emergencies in general (including a fire) when you have pets.
Well for once I've thought I also don't have enough carriers and it's a must. At least enough to put together the ones that get along, however, sone emergencies such as a fire or an earthquake give you little time to make such accommodations.
I still think having enough carriers is important though.
If your apartment is not big that helps too, making it easier to locate as many as you can.
Having means of identification it's a must if worse case scenario you have to just open the door to save their lives. Microchip, tags and tattoo bonanza for everyone so you get a better chance to reunite later. Licesing them helps too. it just takes time to do all this because when multicat household all these expenses multiply by, 9, 10, 12
So one must keep that in mind to do one or 2 at a time until everyone's covered.
I read that licensing dogs and cats has increased the success rate of reuniting pets with their humans a lot.
Keep the carriers in the same place, know your exits. Put a sticker on your door alerting the firefighters how many animals live there with you and who to get a hold of in case of emergency. ..