several logical approaches some of which are

group your wood species by similar if not nearly identical numbers and see how you can get the contrasts you are looking for in the design.
If some of your species are significantly "weaker" in the force moment you are considering than you can T&E the numbers in less critical locations like braces.
Design a "model" frame using the midline numbers from your predominant species labeling the drawing with the caculated load properties.
then by inspection and selection from your list you can replace a stick with the desired color/texture contrast knowing that the properties of the chosen one will fit in the range required from your "model" calculations.
kinda like playing 3D tictactoe using specimen numbers within ranges to pass the engineering specs.
the only caution is to "normalize" the moisture content of the real wood so the drying rates are not at conflict with each other. endgrain sealer big time.
have fun