I'd get a pink "for the masses to think they are cool hikers" backpack.

The reason why pink is because it is highly visible and if you forget it and the family needs to bugout, then can just grab "the pink one" instead of wondering which backpack has the stuff.

https://www.amazon.com/dp/B0761H1R4M

It should be decently low cost so you can put more stuff in, but not crappy.