I know I'm stating the obvious, but as a newcomer here, just please do this.

It might make all the difference.

You are right too do so. Also i would say get the chipped before they are neutered/speyed as well.

all animals should be chipped but in some cases it makes no difference, i know vets that wont check for chips on dead cats, some times chips migrate depending on who puts them in, chips are not a sure thing by any means.

Most people take on other cats without caring whether they are collared or chipped they will feed them and take them in and do as they please