People come up with any kind of scheme to make money! I have seen some advertise "miniature English Bulldog" and charge more $. Take a look at AKC Registry. Is there a place to register "miniature english bulldog"? The dog may be of a smaller statute, but it is STILL an EBD-IF it is registered AKC. If not- ya' pays yer money and ya' takes yer chances! The rescues aren't included, as their papers don't always accompany them.
Many people that sell "Miniature or Micro Bulldogs", are actually selling Bantam Bulldogs. From what I understand, these were originally bred using an English Bulldog and a French Bulldog to gain the smaller stature. They cannot be registered with the AKC, but are recognized by UCA. So, the answer is no, there isn't a miniature English Bulldog.
No. Miniature bulldog just means that genetically, these bullies have been smaller than usual. It is not a separate breed by any means, or any kind of guarantee.
In example, Matilda was supposedly a miniature bulldog. I didn't really want a miniature, I just really liked this particular breeder. Her mother weighed only 32 lbs. Matilda is not even 2 years old and is 52 lbs, and much taller than other bullies we know! She is actually a pretty big female (and in perfect shape according to the vet), so miniature really doesn't mean anything other than "the previous generation was small, so this one probably will be".