French Indochina changed Japan's access to the Indian Ocean

Did Japanese planners expect their long-range cruisers to wage economic war against the British Empire?

They might have wanted that option, but prewar geography and basing made it impractical until French Indochina and Singapore unexpectedly changed Japan's position.

Plans made in the 1920s and 1930s had to assume that Singapore blocked practical access to the Indian Ocean and that Japan lacked forward bases beyond it. The European war unexpectedly changed that geography when German pressure helped Japan obtain French Indochina without a major fight. Capturing Singapore then opened routes that earlier planners could not safely take for granted. Commerce raiding was attractive in principle, but it was not a pragmatic foundation for the original cruiser programme.