Jack

• Same eraHenryLike Jack, it was given most in the 1920s.#5 · steady
• Same rhythmLukeSame beat as Jack: one syllable, ending on a consonant, but it starts differently.#33 · steady
• LongerLucaTwo syllables to Jack's one: a long name beside a short one keeps them distinct.#14 · rising
• RiskyJaceOne letter away from Jack. You'll call the wrong one for years.#114 · steady

Suggestions come from names in this year's top 1,000. Rhythm and rhyme are judged from each name's pronunciation (Wiktionary's, or espeak's reading of the spelling), so a few calls may be off.