Two are needed at each end of the prism
2 octagons (floor and roof), 8 rectangles (walls).
24
Strictly speaking, no, because a semi-regular tessellation must be based on regular polygons and rhombi are not regular polygons. However, octagons and rhombi can be used to make a non-regular tessellation.
A rectangular prism.
Triangles or squares or hexagons. There are also mixtures, like octagons plus squares.
2 octagons (floor and roof), 8 rectangles (walls).
24
i think 14 but im not sure..a total guess actually sorry
Octagons do not make a neat repeating pattern when placed next to each other. Hexagons do make a perfect pattern called a tessellation. To make a continuous grid that includes octagons, you would need to incorporate squares and triangles to fill all the holes in between the octagons. It is much easier for almost brainless insects to make a pattern that is only a single repeating shape than to have to remember how to organize several different shapes.
6 sides are needed
Yes, you can make 768 ÷ 8 = 96 separate octagons.
15 straws are needed
It depends on what type of prism you're using (e.g. triangular prism).
15
seven
9
I have started to make Dove cotes bird houses that are octagonal in shape, the roof also joins the walls and narrows at the top also ending in an Octagonal but much smaller