Hi Mobil, a few things caught my eye right away. The ad for the doll calls her silicone TPE. These are two different materials, incompatible with each other.
This doll will be TPE for that price. Speaking of price, buying from SE will cost you more. They use resellers that will offer the Same doll cheaper.
The other thing I noticed was,, the photos for this doll are a standard photo of a small doll that have circulated all of these sites. Your doll will not look exactly like her, maybe similar, but this doll, I believe is no longer being made.
They like to use these professional photos, and it seems many vendors have and use them, but a factory pic of your doll will be what you are getting.
As for the size and legal. Laws are different all over. Typically, if the doll has bigger boobs and looks like a miniature adult, you should be ok, but everything seems to be open for interpretation. Flat chested dolls are called into question more often, as they look like children.
Best of luck to ya, I hope it all works out for you. Research any company you might order from, we have all heard of scams.