OK, I have 2 main ideas and some secondary ideas in case the main one doesn't suit your interests or the bakery can't do my main idea.
As soon as I thought "mature Beauty and the Beast" as well as anniversary, I pictured the stained glass...
My hope is that the bakeries have access to this artwork so they could make edible images.
Now here's where it gets tricky...I think it would be nice to see the stained glass split up into 4 or 5 separate edible images...and have each image bordered in a thin edible frame and tinted/shimmered to sort of look like the metallic edging on stained glass. The cake could be covered in pretty much any color fondant, but right now I'm seeing blue in my mind. On top of the cake would be the 3D white chocolate Belle topper- edged in gold or silver- and surrounded by red edible sugar roses.
I know it's probably not the easiest thing to visualize, but I'm hoping DD7s 5th bday cake below will better explain it...
In your cake...I'd leave the Belle topper and flowers on top as is...as I could see that being appropriate for a child or an adult. As for the rest of the cake...instead of marbled yellow fondant, picture a marbling of dark and medium blue rolled fondant icing. As for the gold framed characters on the cake...swap those out with the stained glass segments...and just try and picture smaller gaps between the images or a greater number of images. Of course, this idea hinges on them being able to get the edible images of the stained glass.
If you're not into the 3D topper, you could see if they could make this part of the stained glass a 2D stand up topper w/roses...
...and then just decide if you want more images around the sides of the cake or keep it more simple with more red roses around the base.
The rest of my ideas involve the same topper elements (i.e. Belle with the roses or the 2D stained glass), but you could go for a much more subdued and mature cake design if you think the stained glass on the sides is too much or too juvenile (or if they can't do it)...or if skipping it altogether is too dull.
Alternate Suggestion 1- Filigree/Painted Roses
The bakeries that do wedding cakes (GF/BW) would be more likely to be able to do this technique, but I wouldn't rule out the other bakeries.
Alternate Suggestion 2- Piped Scroll Work
They might even be able to work in a few small roses into the mix to tie it in with Belle's roses. The color could also be just about anything that's complimentary to the top.
Alternate Suggestion 3- Molded floral
Best bet here is the bakeries that handle weddings, but these molds/cutters are very common cake tools and if they have one that's roses...it might make for a nice complimentary base design on the cake. Again- you could consider any complimentary colors.
Alternate Suggestion 4- Brush Embroidery Roses
If they're willing to do this technique, they could likely do it with red roses to set off the theme.
Alternate Suggestion 5- (and it's a long shot) Rose Covered Piping
It's a fairly simple technique, but I've never seen the Disney bakeries do it. Still, if they're willing to...darker and lighter yellow roses might look nice...kind of a yellow version of that first 2-tone pink cake.
I hope this isn't too much info, but I wanted to give you a variety of ideas.
Please let me know if you have any questions or need any clarification/more info. You at least have plenty of time before you need the cake.