As pointed out in the comment section, くださる and なさる are irregular verbs in Japanese. The regular imperative form くだされ/なされ somehow changed to ください/なさい long ago, making them look identical to the pre-masu form.
The れ version still exists, but sounds fairly old. You can hear samurai and old sage say 見なされ or 見てくだされ in fictional works.
See also: Proper form of ...
降って【ふって】きて is the te-form of 降る followed by the subsidiary verb (-て)くる in its te-form. くる as a subsidiary verb is very common in Japanese, so you have to get used to it.
降る: "to fall; to move down"
降って: te-form of 降る
降ってくる: "to fall (toward me); to come down"
降ってきて: te-form of 降ってくる "to fall (toward me) (and...)"
が is not &...