Hmmm. Was your neutered male neutered when you had him? If not, I'd double check him testosterone level. If he was cryptorchid (had one retained testicle in his abdomen), he can still 1) impregnant your female and 2) have male dominant traits. CHeck with your vet and you can always get a testosterone blood level done.
I got her as a rescue and before i could get her to the vet to be spayed she went into heat on us. I have always had every dog i owned spayed or neutered, there are too many dogs in shelters.
Is it normal for a neutered male to keep trying to connect with a female? He is able to ejaculate, is this normal? The neutering at 4mths did not cut his dominance down one bit. And he marks his territory.
If the pug was neutered, it's physically impossible for him to impregnate your schnauzer. It may be false pregnancy. I'd recommend bringing her to your vet for a physical exam, x-rays (which will show fetal skeletons around day 45 out of 60), and hormone testing. Unless you plan on breeding her, I'd recommend getting her neutered to help prevent further false pregnancies or accidental breedings!