Is it safe for my dog to lick my kitten's private areas and waste?

It looks like there is a lot of inflammation and possibly blood present around your cat's anus and scrotum. Because your cat is so young this concerns me. I would recommend you keep the dog away from the kitten for now. I'd also recommend taking the kitten in to be checked out by your vet. These young kittens have very weak immune systems and he could get ill very quickly

Yes, you can let them carry on with that as long as they seem to be growing normally and as long as they do not seem to have any health issues. ideally though it would have been better for the kittens to nurse on their mother and same thing with the puppies.

Thanks for using Petco Pet Education Center, formerly Petcoach! This is actually more common than you would think. This is not necessarily of concern in terms of the licking. I would be more concerned though at the possibility of Max chewing and eating pieces of it which may result in gastrointestinal obstruction. For this reason, I would encourage you to try to avoid this behavior as much as possible. Good luck and have a great day!

There is very little you can do other than watch your dog for a few days. Should she get diarrhea, then I would take her to a veterinarian for an exam. There are not that many types of bacteria that your dog can pick up from that and get diarrhea herself.

The kitten is likely still missing its mommy. Kittens normally stay with their mother until 10 to 12 weeks of age, but, unfortunately, humans take them away long before that. So your male's penis is the closest thing to a nipple to get comfort from (suckling is not just for milk but also for comfort).

Unfortunately its hard to tell in the pictures if the skin looks abnormal. It may be that they have some irritation that is making Shiuli very interested in the back end. Are their stools formed or is there some diarrhea? Make sure they are eating a high quality kitten food. Ideally take them both to the vet so that your vet can determine if there is a physical health issue or is this a behavioral issue. Best of luck with them!

Thanks for using Petco Pet Education Center, formerly Petcoach! This is unlikely to become an issue. I would just monitor him for any signs of illness such as inappetence, vomiting, diarrhea and/or lethargy. If any of these are observed, have him evaluated by a veterinarian. Otherwise, he will likely be just fine. Good luck and have a good night!