Sevres Porcelain Napoleon III Cabinet Plates

I have 6 porcelain cabinet plates for which I would appreciate an evaluation.  All 6 are the same pattern and with the same marks on the back and different scenes.  (2 blue, 2 creme, 2 pink colors) Each one has 4 marks: "Bailey Banks & Biddle Philadelphia", "Dore a Sevres" with the letter N under a crown and the number 68 below, "S.46." in a greenish/grayish oval, and "Chateau des Tuileries".  None of the painted areas appear to be signed.  The gilding is worn in some areas, but there are no chips or cracks in the plates at all.

Most of the plates have a raised unglazed spot on the back near the S.46. mark.

I have no experience with what the painted scenes should look like.  Most of the painting is completely flat, with only a few lines in the clothes or details as raised ridges.  I don't see any "brush strokes" other than the raised ridges.  Is this normal or does this mean reproduced?

My obvious question is: are these authentic Sevres?

From what I can gather, the marks may mean that the plate was fired in 1846 and decorated in 1868?  I know that Bailey Banks & Biddle was a high-end jeweler that did carry Sevres porcelain, but I am unable to resolve why all the marks.   Were they created specifically for BB&B?  How does the Tuileries mark fit in?  Is it normal for there to be a long period before decoration?

This is my first instappraisal posting, so thanks in advance, and please let me know if I'm missing any important information.

Good