When you tax a corporation it comes from the revenue and holdings of that corporation

Exactly! And since the "revenue and holdings" of a corporation are owned by the shareholders, it comes from shareholders.

And when the shareholders want to maintain their after-tax income, they can certainly pass the buck to the customers or the employees, to a certain extent.

If a public company can increase prices to increase its profits, it means it is not setting prices correctly!

Prices should be set at the profit-maximizing price. Taxes have nothing to do with it.

Employee compensation is decided by the market.