I'll start by saying that these questions are really ambiguously worded, so im not sure.
1) fine, probably, the questio is abiguous.
2) in the case of perfect substitutes, the consumer is indifferent between consuming x,y or both (in an appropriate ratio). this doesn't sound like the situation psoed by the question.
3) my reading of this is that the marginal utility of meat is zero for mia. what will the IC look like then?
4) these are perfect subsitutes. can you see why?
5) see attached pic