What separates takhalluṣ from iqtiḍāb?

Comprehensive Review and Application: Bayān, Badīʿ and the Final Rhetorical Arts

• Takhalluṣ has a thematic bridge; iqtiḍāb lacks it
• Takhalluṣ only in poetry; iqtiḍāb only in hadith
• Both concern rhyme alone
• Takhalluṣ reverses letters; iqtiḍāb words