I'll be using the plastic figures as a basis for two three man teams, both equipped with bangalore torpedoes and digging tools, so they can double up as any of the three options. The Japanese used long bamboo poles filled with explosives to blow up wire obstacles, so it shouldn't be difficult to model something similar.
I'll try to model some wire cutters if I can but I'll probably just add a spade or pick axe here or there, so that they're non-specific and interchangeable. I also have a three man flamethrower team to put together, so the platoon will be well supported with combat engineers once I've completed the various bases. It's also a bit of a change from bog standard infantry!