Slender man in Legends rules

[m_messiah]

Hello, I think, there is some mistake in rules, which propose misunderstand-able behavior:
Example in rules said, that Diana Cliric of 5 level, with +4 helmet only for clirics, meets Slender man, and beat him, using her ability to trash cards for +3 bonus against Undeads.

But, as we see in description of Slenderman on his card: munchkin not be able to use any bonuses from his/her class or race.

So first question: is Diana able to use her ability against undead, or it is wrong example in rules?
And second question: is Diana must not calculate her helmet bonus, as it is only for clirics, or Slender not beat items, only race/class bonuses?