I would call the American Airlines RTW desk - (800) 247-3247 - and explain your problem to the agents there. AA might be able to take over the ticket from JAL, or at least can help you decide on alternatives. There are various possibilities that would let you get to BKK without transiting Japan (your starting country) or via Hong Kong - e.g. SEA-DFW-ICN-KUL-BKK using AA and Malaysian. If those extra segments would put you over the 16 flight limit, AA has the ability to rewrite the ticket waiving that restriction. They've done so in the past during periods of irregular operations, e.g. strikes, airlines going under (such as Malev Hungarian or Air Berlin) and the coronavirus might be a similar situation. I'd call them regardless.