9 weeks is the average.
NO!
8-13 in the first litter and English mastiffs are pregnant for about 3-4 months(93-124).
Yes, it is possible. A stillborn does not mean the entire litter will be. It is especially common in a cat's first litter for there to be one or more that didn't make it.
A cat can get pregnant again (near enough) straight after giving birth but usually doesn't until she has finished weaning her kittens. This is because she cares for them until they can fend for themselves BUT hypothetically can get pregnant again straight away
You can breed a rabbit any time, even if she is 2 weeks pregnant so she will have a litter after the first every two weeks with a maximum of about 18 per litter, but double breeding is not healthy. so yes they can have a lot of kits.
No, but it is impossible to tell exactly when her first estrus will occur. Normally a pup will go into heat sometime in her sixth month, but is she is early, she may become pregnant without your knowledge.
A group of puppies is called a litter. The size of a litter can vary drastically based on the breed and if it is the dogs first litter.
Simply because it was her first litter. It is likely that if she has a second litter, she'll have more.
Hoping that you mean litter. This means that you have first choice of which one you want to take from the first born in the first litter.
If you're on birth control pills for the first time, you don't have any more of a risk of getting pregnant than you normally would if you have been on them for a long period of time.
With proper care the litter survives, if you are not sure, take your cat and its litter to the Veterinarian.
You are right to think that if your Staffy has a solid black saddle that it may be a mixed breed as this marking is not seen in pedigree Staffordshire Bull Terriers. There are many breeds that have black saddles, including Beagles, Jack Russells, Fox Terriers, German Shepherds and so many more. It would be impossible for me to identify what breed your Staffy is crossed with without first seeing a picture though.