Two buttons control the power supply of the ardina + are used as digital inputs, is there any danger?

Question

Arduino

Hello, there is the following scheme:

It works like this: when one of the buttons is pressed, power is supplied to the Arduino, then the state of the inputs (7 or 8) determines which button was pressed and some action is performed. Question: being powered by a 12 volt battery, through the RAW pin (which has an internal regulator), is there any chance of burning the board or digital pin?
Version with optocouplers:

Answer 1

There is a possibility, depending on the diode: there will be a negative voltage on the pin (relative to GND), equal to the voltage drop across the diode. For silicon diodes, the threshold voltage is about 0.4..1.0V, for Schottky - 0.1..0.3V. And from the datasheet on the mega:

Absolute Maximum Ratings
Voltage on any Pin except RESET
with respect to Ground ................................-0.5V to VCC+0.5V

Answer 2

There is a chance to get an unknown what instead of the result of the work, because the controller will be powered by the devil knows how due to the bounce of the contacts.
Such things are done using the sleep mode of the controller with wake-up interruption from a change in the state of the input.

Answer 3

Changed to optocouplers. Am I right that this circuit is free from all the above disadvantages?