Please need help!

Hi, I have just recently gotten involved with fostering shelter dogs. I recently noticed one of my fosters has worms, YUCK, I noticed some in his poo. I am really worried about my two 8mo old kittens. They play with these dogs, lick them, and lick the floor where they play. Are they at risk of catching anything??? One of the kittens has been having watery poo, lovely I know, and it looks like there is a tiny bit of blood in the stool, but I am not sure!
I am planning on taking both of the cats poo in for a fecal exam but I heard the vet can only detect 20% OF PARASITES! THATS SO SCARY!
If he doesn't find anything wrong with them should I still deworm my kittens with something? And what should I deworm them with? Is there anything that can kill all possible parasites? Im so worried about them, I couldn't live if anything happened to my two babies I might have to just take them to the vet but it is just getting so expensive so I was seeing if there was a cheaper way I could find out what is wrong and treat them. But NOTHING that could be a risk to their health. I would rather just be in debt and not eat for a couple weeks ha. Please let me know ASAP! THANKS

If your vet does not feel the need to deworm your animals, then I wouldn't deworm them. The over-the-counter medications you will buy are ineffective, and some will do more harm than good. Blood in the stool isn't always because of parasitic invasions. There are other reasons why the stool is bloody, watery or mucousy. Again, let your vet guide you in this.