Welcome to YT!
It was very kind of you to take this little one into your home after her previous owner passed away. How very sad and frightening for this little girl.
You have a multi-layered issues so I would like to break it down a little at a time.
First off, did you know that she can be spayed right now? It might be best for her health and well being if you considered this option. If the vet thinks she is older than 4 yrs it could be very dangerous for her to have a litter of puppies. In addition, you do not know if she has any health issues that she could possibly pass on to puppies. Or even if she would be able to have a litter without a c section.
Oral care in a Yorkie is a huge issue. It sounds to me that she needs a good dental cleaning and possibly tooth extractions to correct this problem. Brushing will unfortunately NOT fix this issue and it can actually become life threatening if left untreated. Mostly likely she has infection in her mouth that needs to be treated with an antibiotic. A dental can be done during a spay and the cost will then be minimal. I am not sure about the teeth *if* she is pregnant and you decided not to spay now. You might be able to get a better answer from a breeder on this portion of your question.
As for her being afraid of you husband, it will just take a lot of time and patience for her to accept him. What might help is if he sits on the ground at her level with the treats he is offering, while speaking in a comforting voice. He should never try to reach out for her to pet and but allow her to come to him. Let her "get acquainted" at her own pace and do not force the issue. She might have been treated poorly in her former home by a male.
If you have any other questions you can always send me a PM as I want to help.