# one of these little ones

"one of these lowly ones" or "the least important of these." This refers to Jesus's disciples.

# in the name of a disciple

"because that person is a disciple" or "because he knows that that person is a disciple."

# he will ... his reward

Here "he" and "his" refer to the one who is giving.

# he will in no way lose his reward

This is not about having a possession taken away. Alternate translation: "he will certainly receive his reward"