I'm not sure why people find this confusing.
1) Can you normally cast spell [whatever] on your familiar? If so, you can cast it on the familiar.
2) Could you cast spell [whatever] on your familiar if the spell were able to be cast on others (i.e. not just "you")? If so, you can cast it on the familiar.
2) Could you cast spell [whatever] on your familiar if the familiar were of the appropriate creature type (i.e. something other than "magical beast")? If so, you can cast it on the familiar.
It's just not that complicated.