Thom Dunn published an article on Oct 25, 2021, Bugs Bunny’s Official D&D Character Sheet Is A 15th-level Illusionist, which brought about some ideas, which follow.

Dragon Magazine #41 was published in April 1981.

Bugs Bunny

Originally, Bugs Bunny was a 15th level Illusionist from the 1980’s Advanced Dungeons & Dragons.

For D&D5e I’d say Bugs is a 15th level Sorcerer Rabbitfolk.

Rabbitfolk being from UNEARTHED ARCANA 2021 Folk of the Feywild

Popeye

AD&D: 9th-lvl Fighter and 18th-lvl Fighter

D&D5e: 15th-lvl Human(variant) Zealot Barbarian with the Sailor background.

Marvin the Martian

AD&D: 7th-lvl Fighter

D&D5e: 7th-lvl Rock Gnome Artillerist Artificer

Foundry VTT

Here are the Foundry VTT Actor sheets for a few Looney Tune characters