This is our planned bathroom layout (bathroom is 83" deep by 91" wide or approx 7' x 7.5'). FYI: Window is on right wall and door is on bottom wall.

The showroom has two marble basketweave tiles available at a discount. The two sets of tiles are exactly the same, except the size of the basketweave is different.
Tile 1: Basketweave 1 1/8" x 2" (22 sq ft available)
Tile 2: Basketweave 3/4" x 1 5/8" (21 sq ft available)

I would like to incorporate the basketweave tile as a "rug" in the center of our room, shower floor, and shower niche. The rest of the floor will have marble 12x12 or 6x12 around it. I am just not quite sure we would have enough of of one set of basketweave tile to work with.

Option 1: 24"x71" (12 sq ft) rug centered on floor (6" from back wall and 6" from front entry wall). Shower floor could be anywhere from 9 - 10 sq ft (we are moving the toilet in order to make some extra shower room and we are not sure how much they will be able to move the toilet until work starts). This puts us at 21 - 22 sq feet without any extra tile to spare or tile for shower niche. Way to scary for me...what if we break a tile?

Option 2: Make a smaller rug 24"x59" (10 sq ft) that is 12' off front and back walls. Shower floor would still be 9 - 10 sq ft. That puts us at 19 - 20 sq ft. Do you think we would still have tile left for a shower niche? I am not sure how big a niche typically is.

Option 3: Just use the basketweave for the "rug" and in the shower niche and use something different for the shower floor.

Option 4: Mix the two tiles. So use the larger basketweave for the floor rug and then use the smaller basketweave for the shower floor and shower niches. Then we would have enough with tile to spare. Do you think that would look odd in such a small bathroom. The shower will be all open (glass walls), but there will be a shower curb separating
the two floors.

Thoughts. Does this sound like it will look like a hodge podge? Can we make this work or am I just dreaming? I want honest opinions here. No matter how much of a deal it is, it's not worth it if it won't look right.

Thinking of doing a skinny "rug" similar to this bathroom and then doing the same tile on the shower floor (as we don't have a tub).

21 sf should be plenty for a rug and the niche, or possibly the rug and the shower floor, but as you said it is cutting it very close. You could do a border out of 4x12 or even 6x12 around the basketweave in the shower.. mimicking the main floor, then you might be able to put it in the niche as well.

L0astly, I would not mix the two. It might look like you ran out of one and had to get another.. KWIM?

I would use the darker one for the "rug" and maybe the alcove rear, and the lighter one in the shower floor.

Make sure the surrounding plain granite is REALLY matching the grey in the mosaic.

The differing scale is interesting, but they are the same color and pattern, which is not a "hodgepodge".