I agree that CSA might not last long enough, or spread enough, to ever directly affect Asia.
However, the weaker USA that an ACW loss would yield would have an impact, thought the degree would really depend on the terms of the ACW armistice and whether CSA truly develops as a separate country over the long term.
Assuming the CSA lasts, or at least lasts a few decades, the weaker US would spread somewhat more slowly, might never have a Spanish-American War (being less/later involved in the Pacific and not near to Cuba), and might not ever get the Phillipines, but probably still gets Hawaii. In general, the US would likely have less interest/influence in the Western Pacific (near Asia).
Further, if there is no Spanish-American War, Teddy might not become president, so someone else negotiates the end to the Russo-Japanese War.
In theory, it might change the terms of the Naval Treaty and the inter-war relationship between the US and Japan. If the US doesn't have the Phillipines, it removes a significant thorn in the Japanese side that might tweak their targets, even IF they do still attack the US.