How do you see it?

Hi,

Would you make them possessive and if so why?

human rights violation -- the violation of human rights (looks to be a candidate for possessiveness but written as that because it is idiomatic)

House ethics panel -- the panel concerning ??House ethics?? (seems doesn't need to be made possessive)

Doesn't anyone have good tips to guide me?

Neither of these is possessive.

Human rights violation - yes this means the violation of human rights.  You are getting confused because rights ends with s. The s shows a plural not possessive. Not every 'of' shows possessive.

It is similar to 'rules breaking'. Would you want to make that possessive?