Well, it is always a dilemma whether the piece icons should hint at their name or hint at their move. For playing a variant there is really no need for knowing the names of the pieces at all. You must associate images with moves. So this is why I prefer the second method. Especially since names in chess variants are not standardized at all, and pieces of the same name can have totally different moves in other variants. So no matter what the name of the piece was, if it moves similar to a Bishop, I would represent by an image that looks like a Bishop. Even when it was called a Bicycle or a Bat. E.g. the diagram in the Elven Chess article uses the images for Crowned Bishop, Crowned Rook and Lion for the Elf, Goblin and Warlock. The diagrams for Sac Chess in your book do the same for Missionary and Sailor.
Well, it is always a dilemma whether the piece icons should hint at their name or hint at their move. For playing a variant there is really no need for knowing the names of the pieces at all. You must associate images with moves. So this is why I prefer the second method. Especially since names in chess variants are not standardized at all, and pieces of the same name can have totally different moves in other variants. So no matter what the name of the piece was, if it moves similar to a Bishop, I would represent by an image that looks like a Bishop. Even when it was called a Bicycle or a Bat. E.g. the diagram in the Elven Chess article uses the images for Crowned Bishop, Crowned Rook and Lion for the Elf, Goblin and Warlock. The diagrams for Sac Chess in your book do the same for Missionary and Sailor.