Don't really think they will need it, but if only for the worried cat-parents sake, I'm wishing your furbabies a safe surgery & a quick recovery! Good luck to them!
But please, don't fret too much. If you worry a lot, they might sense this and be concerned and scared, too! Really, cats know this stuff. Everything will go smoothly, and they will be fine, okay?
And the thing about the stitches, well my cats did try and pick and chew them out a bit but it's easy to get fixed up at the vet's when you need to. And dissolving stitches are a good idea, if possible. Now just try to relax, remember worrying doesn't help. But I'm glad to see you care so much about your furbabies!!
A ton of us on TCS have been through all this worrying and we understand, keep us updated, I would like to know when they are done and how they are doing!