Why does it say "[v'Hinachtem] Shimchem li'Shvu'ah"?
Rashi: One will take from your name a curse and Shevu'ah for generations - 'if will not happen to you like happened to Ploni.'
Radak: This is bodily punishment. No man knows punishment of the Nefesh. When your bodies will die via the sword, you will leave your names for a curse and Shevu'ah, the opposite of a Tzadik - "Zecher Tzadik li'Vrachah" (Mishlei 10:7). My chosen ones will curse via you - so and so will be, and Hashem will kill you like He killed Ploni. This is like Melech Bavel cursed Tzidkiyah and Achav - "v'Lukach Mehem Kelalah l'Chol Galus Yehudah... Yesimcha Hashem k'Tzidkiyah uch'Echav Asher Kalam Melech Bavel ba'Esh" (Yirmeyah 29:22). Li'Shevu'ah is like li'Kelalah, for in a Shevu'ah one mentions a curse, e.g. 'I will be such and such if I did this.'
Malbim: It says v'Hinachtem, for you will not die immediately. First your name will be for a curse - due to your great afflictions, people will swear 'so should happen to Ploni.'
How will he kill them?
Rashi: It will be permanent death.
Radak citing Targum Yonasan: It will be a second death 1 .
Malbim: Each will die a different abnormal death.
Presumably, this means in the world to come, like Rashi explained. (PF)
What other name will His servants have?
Rashi: It will be good repute and mentioned for Brachah. Radak - e.g. "Becha Yevareh Yisrael Leimor Yesimcha Elokim k'Efrayim vechi'Menasheh" (Bereishis 48:20). This is the opposite of Resha'im's name.
Malbim: If one's name was like the Rasha's name, he will change his name. Resha'im's name will be for a curse and Shevu'ah only initially. Afterwards, Hashem will kill them and change His servants' names 1 , and the Resha'im's names will be totally forgotten.
Initially, Malbim implies that the Tzadikim will choose to change their names. Perhaps He will cause them to want to do so. (PF)