How so? How are you defining 'fungible'? It already is by the standard economic definition https://en.wikipedia.org/wiki/Fungibility
Since BCH uses a public ledger, the gov could track if I illegally bought cocaine and the BCH I used could be considered "dirty" by other people. Short explanation.
Yes and no. With Monero, it seems protocol level privacy is the superior solution. As evidenced by this thread however, the first step is to get the community to actually care.
Yes. Coin-shuffle is an extra step, but it is available right now. Guessing that, in time, periodic shuffling is going to be a built-in feature in most decent wallets.