• ṛtvijaḥ — priests
  From ṛtu (season) + √yaj. The priests who officiate by season. Gauḍīyas note that the ṛtvij is a specialist; for Vasudeva's yajña the sages themselves serve as ṛtvijas — an extraordinary upgrading of the office.
• sadasyāḥ — officiating members of the assembly
  From sadas (assembly hall). The expert witnesses. Gauḍīyas read the sadasyas as a kind of internal review board — yajña is not done in private; it is done before a learned assembly.
• vṛtra-haṇaḥ — of the killer of Vṛtra (Indra)
  vṛtra (the asura) + han (killer). Indra. The simile names his adhvara (sacrifice) as the benchmark. Gauḍīyas read the simile carefully — even Indra's sacrifice is the comparand, not the original; Vasudeva's yajña stands above it because Bhagavān is its center.
• virejuḥ — they appeared effulgent
  From vi + √rāj (to shine forth). The priests literally radiated. Gauḍīyas treat radiance in such verses as Bhagavān's prabhā showing through His servants — the priests shine because they are doing what they are made for.

• Where has carelessness in form leaked into my spiritual practice?
• What small upgrade in care could lift my next devotional act?

The ṛtvijas in silk and jewels look as if Indra's own sacrificial arena had been transposed to Kurukṣetra. The simile is precise: Vasudeva's yajña is being explicitly framed as on par with the deva-yajña of the conqueror of Vṛtra, with the additional dignity that here Bhagavān Himself is present in the assembly.