1.Is it OK for subordinates to interview candidates for their boss's role?

No, and I would consider it a serious red flag for me as a candidate

It would bother me a little, but I wouldn't consider it a serious red flag

I'm OK either way, it doesn't really bother me

I think it's a good idea for subordinates to interview the candidates

2.If you DON'T think it's a good idea, why?

3.If you DO think it's a good idea, why?