Whoever/whomever

In isolation, the sentence is not obviously correct with either. However, it may be better when seen in a full context, I suppose with the meaning "Whoever her ex-dates are, she really doesn't care". In any case, I see no reason to use "whomever".

Then, how about the following ones?

1. [Whoever/Whomever] they are talking about, I really have no interest.
2. [Whoever/Whomever] we interview, we never ask applicants' educational backgrounds, except that they are directly related to the positions which candidates apply for.

Technically they should be "whomever". However, "whomever" is a formal and difficult-looking word which many people would avoid. As with "who"/"whom", except in the most formal language, "whoever" tends to be used in all cases.

(2) has a problem at the end. You can say "except when this is directly relevant to the positions which they are applying for". However, it seems to me that educat

Actually, I don't like #2 either with the same reason. So, I revised it. Could you check the following one again? Thank you.

[Whoever/Whomever] we interview, we never ask applicants' educational backgrounds, except that they are required for special purpose such as permission or license essential for their duties.