How an extended Pacific war would redirect Atlantic escorts

Would Atlantic convoys still need the same escort effort if the war continued against Japan after Germany's defeat?

No; Japanese submarines were unlikely to sustain an Atlantic threat, so anti-submarine forces could shift toward the Red Sea and Indian Ocean approaches.

Japan was unlikely to recreate the German submarine threat in the Atlantic. The existing Atlantic convoy system could therefore contract once Germany was defeated. Escort carriers and other anti-submarine groups could instead protect the Red Sea and hunt submarines in the Indian Ocean, guarding the routes that mattered to the Pacific buildup. Theater strategy directly governs the redeployment of escorts and shipping protection.