But ultimately, decision to go to war is with Eleven, and will involve more careful assessment of cost.
So I say that all-out citizen boycott to ramp up the costs, is the best response, while the military prepares to launch a riposte through Indus and Akshay Hind. Unfortunately there is no such thing as Iyersan's Limited Jhapad possible. If they attack, defense is a stupid option. Massive 3-pronged invasion cutting off entire Han force in Uttar Dharmasala (UD) is the best bet, as extreme as the immediate cost will be to India in the short term. Extend the LAC to the northern/eastern borders of UD.
The thing is: CPC Dons understand very well that ANY purely conventional attack against India will (in a strategic sense) only lead to a loss for them. IF they try to fight us in a muh-thod, frontal-attack kind of way that is being anticipated by some: rockets, MRBMs, invading across the LAC etc. the big picture outcome for them will not be good. This is doubly true if they try a frontal attack in the Doklam theatre, where our conventional advantage is maximum, but broadly it is true if they try it in any theatre from Ladakh to Walung.
Best case for China: it will be a stalemate. Many military casualties on both sides, attrition of assets/infra on both sides, but in the end they will have no significant territorial gains to show for it. Politically it will be a loss, because it will completely explode the supel-powel myth of being able to enforce their national will through massive superiority. If Clinton (or Bush, or any of the globalist order) had been in power in the US, Beijing could have relied on American (and broadly Western) media/stink-tank support to try and pass the whole thing off as a "victory" for them on the world stage. Nowadays, they will be happily exposed as the same paper dlagon that got its butt whipped by Vietnam in 1979.
Worst case for China: their attack leads to a gang-bang on multiple fronts where the US, SoKo, Japan, India, and perhaps other countries all get their kicks in, cleaving off huge chunks of claimed territory and humiliating the PLA/PLAN/PLAAF thoroughly. And/or, the N-word. Either way, dreams of becoming the 21st century supel-powel go completely down the drain.
Therefore: whatever they do will not be purely (or even mostly) a conventional muh-thod attack. It may have some component of conventional air-land strikes, missile/rocket attacks or whatever. But they will rather try and follow the example of the Russians in their recent wars: Georgia 2008 and Ukraine/Crimea 2013-present. 4GW. Non-state actors, proxy fighters, attacks on economic interests, information warfare, backed up by actual PLA muscle only when the exhaustion and demoralization of their enemy gives them a clear field of advantage in certain theatres of choice. And always, always, with a well-defined goal in mind.
Two well-defined goals for them would be (1) Arunachal Pradesh, esp. Tawang (2) J&K, with the intent of securing CPEC.
I would think about future scenarios with the above caveats in mind.