If Japan aren’t going it makes no difference to Worlds qualification. The team qualifiers will be the top two excluding China and Japan.
South Korea will almost certainly qualify. Taiwan were the 4th team last year, 8 points clear of 5th place. I’m not familiar with the rest of the Philippines team but I suspect they would be very dependent on good scores from Finnegan and Malabuyo to challenge Taiwan. If they score similarly to Finnegan at the SEA Games they will comfortably qualify as individuals but team might be a stretch.
Also, Japan have sent by my count 17 women to five international meets so far this year, but have no interest in the Asian Championships? I think they have a domestic competition next month so maybe that’s why, but still, AGU can’t be happy with that.