• taptān — (those) afflicted, lamenting
  Past participle of √tap — to be heated, pained. Kaṁsa anticipates the family's grief and treats it as cause for further killing. Asura-logic: their pain proves they love what I want destroyed; therefore destroy them too.
• vasudeva - purogamān — headed by Vasudeva
  Vasudeva + puroga (going in front, foremost). Vasudeva is named the leader of the relatives — the same Vasudeva Nārada has just exposed as Bhagavān's father. Kaṁsa's full extermination-target.
• vṛṣṇi - bhoja - daśārhakān — the Vṛṣṇis, Bhojas, and Daśārhas
  Three Yadu sub-clans. The Bhāgavatam names them because the Yadu-vaṁśa is the Lord's own appearance-lineage; Kaṁsa's plan is to annihilate it entirely, which makes it the chapter's most pointed adharma.
• nihaniṣyāmi — I shall kill
  Future of ni + √han. The first-person killing-verb in Kaṁsa's mouth is in the future tense — a future Bhagavān has already cancelled.

• Where is a destructive habit in your life expanding beyond its original target?
• Whom are you in danger of harming through escalation you haven't yet named?

Kaṁsa's list is generational: kill the boys, then the parents, then every relative who mourns them. Hatred without an off-switch is its own form of theology — a perfect inverse of bhakti's all-inclusive love. The Bhāgavatam puts the speech in his mouth so we can hear the contour exactly.