No. That is not the most widely-discussed plan, AAR. Which would be >=75% for a full difficulty period, and another difficulty period (not dropping below 75%) for other wallets to upgrade. Only then create the first large block. Presuming, of course, they stick to that plan.
Of course, some other large blocker may jump the gun. But a premature large block would likely be orphaned off by all the other BU miners.
Umm... presumably you are aware that, even if there were patents or copyrights on Bitcoin preventing its free use, they would be unenforceable in a permissionless environment, right?
That should be a real problem. So they will force community to accept their fork if no consensus reached.
Well, no. Not really. They can slow it down, as difficulty is predicated on current network hash power. If 50% of the miners start hashing blocks that core will not validate, the core (and fork) block interval will be slowed to 20 minutes. If the fork occurred at 75%, core blocks would slow to 40 minutes. Which would increase competition for block space, driving up fees. BU blocks would slow to ~13 minutes, but have increased transactions per block, so throughput would actually be increased on the BU fork. Decreasing competition for block space, thereby driving down fees on the BU chain.
But yes, the likely result is that all but an intransigent few would migrate to BU. Because it would be functional, and the core chain would be largely not.