Trump's Quad allies in Asia fret over tariffs as China factor complicates ties / Aukus, Quad will have to step up under Trump's Indo-Pacific stance / Message to China: Quad opposes unilateral acts to forcibly alter status quo / Rubio's first order of business: Meeting Quad's foreign secretaries / US consensus on countering China will keep Quad relevant under Trump: experts / Quad plans to hold joint coastguard training to counter China in Indo-Pacific: experts / Aukus, Quad allies could face pressure on China from next Trump administration / Quad's maritime partnership signals pledge to counter China, expand its scope: analysts / US parties find unity in Quad's potential to counter China in the Indo-Pacific / China 'testing us', says Biden in hot mic remarks to Quad allies