Mark 6 study questions

Why do the disciples anoint the sick with oil? (v 13 and James 5 v 14)

The disciples have sandals in Mark 6 v 9 but in Matthew 10 v 10 Jesus tells them not to take sandals. Why is there is this difference?

Both Herod and Ahasuerus in Esther promise to give up to half of their kingdom. (v 24 and Esther 5 v 3, 7 v 2) Is there any sgnificance in this?

What does the fact the disciples did understand the loaves have to do with being scared when Jesus was walking on water? (v 52)