Jesus is talking to a group of people about what they as individuals should and should not do. All occurrences of "you" and "your" in verses 5 and 7 are plural; in verse 6 they are singular, but in some languages they may need to be plural. (See: [[rc://en/ta/man/translate/figs-you]])
It is implied that those who see them will give them honor. This can be stated in active form. AT: "so that people will see them and give them honor" (See: [[rc://en/ta/man/translate/figs-explicit]] and [[rc://en/ta/man/translate/figs-activepassive]])
Possible meanings are 1) no one can see God. AT: "Father, who is invi"sible" or 2) God is in that private place with the praying person. AT: "Father, who is with you in private"
Possible meanings are 1) the repetitions are useless. AT: "do not keep uselessly saying things over and over again" or 2) the words or sentences are meaningless. AT: "do not keeping repeating meaningless words"