I heard if you release a domesticated pig into the wild it becomes a wild pig.

all pigs were domesticated at one time, I have had pigs with tusks, the Bores pigs grow tusks to dig in the ground, the oink is when they communicate with each other,

Yes they do revert over time in the wild. I just saw a feral pig on reddit and it was an obvious pet/livestock breed but with coarse fur

In my experience, the wree wree wree is mostly from piglets. Older pigs tend to grunt as they root in their food, and some of the grunts sound like a husky oink.

It's only a feral pig at first, generations later it'll have black fur and long tusks.

Pigs oink when they are rooting around in the ground.
They go "WREE WREE WREE!" when they're having sex, which of course is understandable.

Not true baby just made it up
And they do go oink and also wree