It's possible to use send keys for the first two operations you describe. Take a look at the thread on this forum for some examples. https://powershell.org/forums/topic/sendkeys/
For the third....hmm depending on your operating system, it may also be possible to use your NumberLock keys, but this can be pretty specific. In other circumstances you would probably need to enable the Ease of Access to specifically use the keyboard.
For fourth, not certain on specific coords, and bear in mind these will always be relative to the screen resolution. As such you'll never be able to ensure you're actually clicking on the right location. You could use SendKeys in combination with some API functions to try and activate the specific window, and then activate the specific control before using SendKeys to simulate the click.