A family size meal should have enough to at least be the entree for four people. With enchiladas that means two per person, not one. It's a corn tortilla with stuff rolled in it, barely larger than a taquito, you need two for it to not look like a depression meal (we're already cooking frozen enchiladas, we're there already, it doesn't need to be rubbed in).

I've noticed that sizes are shifting. Party size is now what used to be family size and can actually feed four, sometimes it's called mega family size or some bullshit. Family size now means two adults and maybe a child <10 yrs. I remember a family size lasagna had leftovers when I was a kid.