First, if you plan to continue helping the critters out for more than a year, go ahead and buy a trap, if you can swing it. Lowe's usually has them for about forty bucks - better price than I've seen on line. Too, you may be able just to borrow them from your local humane society.
Second, alteration and rabies vax are a must, but also ask for an eartip. Look at this, created for my web site by a fellow DUer:
The tipping of the left ear (some vets use a notch,* and some may use the right ear) is so that you can easily identify cats you have already altered. If you get an eartipped cat in a trap (unlikely - they learn), it is best to get a rabies booster but at least you know you don't have to take it for alteration.
Please let your neighbor know that if the kits are old enough to run with mama, they are too wild to be tamed. Your best bet is to trap all three. I STRONGLY suggest having as many traps as cats you want to trap (this is where borrowing comes in handy) and set out all traps at once. As I said, they learn. If one cat sees another cat get trapped, chances are it'll be wary enough not to go in itself.
Anything really smelly will do, although I'd go for tuna or even a smear of anchovy paste vs canned cat food. You don't have to put down too much food -- just enough for the odor. Oil-packed tuna is better than water-packed.
Other trapping tips: (1) tape newspaper into the trap from the entrance to the back. Cats don't like to step on things that their paws can squish through. Also, the newspaper at the end of the trap gives you something to put the food on. (2) COVER the top, sides and back of the traps! Burlap or old towels are best. If the cats can see out they are far more likely to panic and rage inside the trap. They could hurt themselves, or, more likely, scare you into letting them go out of
fear that they'd hurt themselves. KEEP the traps covered the whole time, from trapping to transport to release.
Lots of info, I know. Please PM me any time. I'll help you as much as I can.
You can find tons of info on www.alleycats.org -- my best resource.
Good luck! :yourock: !!!
* I much prefer the tip to the notch, because the notch can look like a healed-up fight injury.