Some of the questions are easier than the others.
2 and 4, with "rarely" and "seldom", refer to how often something happens. "if ever" also refers to how often something happens.
'He rarely, if ever, is late for work.' This means that, as far as I know, he is either never late for work or he is rarely late for work.
In 5, "who" refers to a person. And "anyone" is the only choice that clearly refers to a person.
'Who, if anyone, can solve that problem?'
1.. Her expressions, if (she has) any (expressions), do not match the occasion. This means that sometimes she may not have an expression, but when she has an expression it doesn't match the occasion.
3.. "if anything" is often used when there is uncertainty or doubt about something. Sentence 3 means that abuses might not have definitely changed. But if there is a change, it seems the change is to more abuses, not less.
'If anything, we have too much food.'
This sentence means that we might have just the right amount of food. But if it's not exactly the right amount, it's too much food. We don't have too little food.
I hope the above helps.