It would appear not to be a violation of the New York Penal Law, section 265.01 to possess a sword. per se. However, under section 120.15 of the New York Penal Law, a person carrying a deadly weapon in public could be charged with the crime of "menacing" in the third degree.
Sec. 265.01 states:
New York - Penal Law Section 265.01. A person is guilty of
criminal possession of a weapon in the fourth degree when:
(1) He possesses any firearm, electronic dart gun, electronic stun
gun, gravity knife, switchblade knife, pilum ballistic knife, metal
knuckle knife, cane sword, billy, blackjack, bludgeon, metal knuckles,
chuka stick, sand bag, sandclub, wrist-brace type slingshot or
slungshot, shirken or "Kung Fu star"; or
(2) He possesses any dagger, dangerous knife, dirk, razor, stiletto,
imitation pistol, or any other dangerous or deadly instrument or weapon
with intent to use the same unlawfully against another; or
(5) He possesses any dangerous or deadly weapon and is not a
citizen of the United States...
Criminal possession of a weapon in the fourth degree is a class A
Further, Sec. 120.15 states as follows:
§ 120.15 Menacing in the third degree.
A person is guilty of menacing in the third degree when, by physical
menace, he or she intentionally places or attempts to place another
person in fear of death, imminent serious physical injury or physical
Menacing in the third degree is a class B misdemeanor.
You may want to take the sword(s) to a local police station in New York City. Ask to speak to someone in command. Present the sword and ask the command officer if you would be in danger of being arrested by carrying the sword. You may also tell the officer that you intend to dress in costume.
I doubt, every highly, that you will be able to carry the dagger replica.
I hope you find this information useful and that you PRESS THE GREEN ACCEPT BUTTON so that I can get credit for answering the question. Thank you.