Availability of Okoume isn't very good outside of areas with a marine industry, and it is really pricey. It's also softer than Baltic birch. BS1088 is really nice, but if you can find it the second-quality 6566 is just as strong and fine for robots. The difference is that 6566 is allowed to have more surface imperfections than 1088. I can't say that I've noticed any other differences in building boats.
To some extent I was having fun here -- baltic birch should be fine in this application.
Occasionally I've seen references on CD to using various hardwood plywoods on robots. Don't do it. Hardwood plywood (oak, maple, cherry, etc.) is a thin veneer of hardwood over a softwood core, and that core can and does have gaps, voids, splits and other horrid imperfections. OK for cabinets, but not for uses where you count on its strength.
Regardless of wood species you want a plywood with an odd number of layers where every layer (including the surface) is the same thickness, and the core is made of the same species as the face.
Maybe our team needs to add FRC to our program just so we can build a WoodyBot.
The name would certainly fit in with FIRST.