Is it permissible to marry the daughter of one's paternal uncle who is five years younger than the questioner, knowing that the questioner was nursed for one night with her older sister?

Suckling establishes the same prohibitions as lineage. So, whoever suckles from a woman becomes a son to her and her husband, and all their children become siblings to him. This applies specifically to the suckled individual, not to his brothers and sisters. If you suckled from the girl's mother or from her father's wife (due to the husband's milk), then it is unlawful for you to marry her. However, if you shared suckling with her sister from a woman who does not establish a prohibitory relationship for you, then the girl is not unlawful for you. The suckling that establishes prohibition requires five full sucklings. If this condition is not met, then there is no harm in you marrying her.