It sounds like many of these requirements are for safety and reliability.

I can imagine that participants in a war would be much more risk-tolerant than a typical team of professionals would be. Maybe they're okay with a high-ish chance of failure, injury, or death, and so they resource the mission within the limits of what they have, or what they believe will pass unnoticed?

The Germans believe that there were several people. Not 10, but several. The constraint was that they had to be able to pose as vacationers.

Skepticism is warranted for sure, but we shouldn't underestimate what highly motivated and courageous people can do.