JS clarifies that beasts in Revelation 4:6 are individual beasts.
"Answers to Questions, between circa 4 and circa 20 March 1832 [D&C 77]," 141, The Joseph Smith Papers website, accessed March 24, 2021
Q What are we to understand by the four beasts spoken of by John in the 4 Chapt. & 6 verse of Revelations? A They are figurative Expressions used by the revelator John in disscribing heaven the paradise of God the hapiness of men and of beasts and of creeping things and of the fowls of the air that which is spiritual being in the likeness of that which is temporal and that which is temporal in the likeness of that which is spiritual the Spirit of man in the likeness of his person as also the spirit of the beast and every other creature which God has created Q Are the four beasts limited to individual Beasts or do they represent classes or orders? Ans They are limited to four individual beasts which were shewn to John to represent the glory of the classes of beings in their destined order or sphere of creation in the enjoyment of their eternal felicity.