If the Bad Guys are in an undercover mission, I was thinking that maybe Diane could sing on stage at a jazz club while disguised as possibly a black woman like her voice actress.
Since the Bad Guys and Diane are now secret agents, and everyone became suspicious of them to begin with, they could probably use high-tech disguise solutions to not be easily recognized in a human environment. I was thinking that their human disguises could look a similar to their voice actors. It could be possible for Wolf, Diane, and Shark, but here are thoughts of how Snake, Piranha, and Webs could use these holographic disguises;
1. SNAKE: His holographic projection would need to be a full-body rig that translates his slithering movement into a bipedal gait. Imagine a device that projects a human form while a mechanical internal framework (or the hologram itself) supports his weight, allowing him to "walk." A humorous element could be his discomfort with the human form, perhaps feeling awkward having legs for the first time, leading to some clumsy or exaggerated movements.
2. PIRANHA: His hologram would act as an "exosuit" of light, scaling him up to a standard human height. This would provide him with the necessary height and limb length to blend in at any social event. Given his energetic personality, his disguise might glitch when he gets excited, occasionally flickering back to his true, smaller form during high-stakes moments.
3. WEBS: She would likely be the one to refine and calibrate the holographic projectors. Her disguise would be the most technologically advanced, potentially allowing her to project multiple "human" appearances depending on the mission requirements. Like Snake, she would need a projection that handles her extra limbs, perhaps by rendering them as human arms and legs or by cleverly folding them beneath a bulky coat or dress in the holographic projection.