Replace function on plugin that works with WooCommerce

Hello

I need help in replacing a function that is not pluggable from a plugin that I use with WooCommerce in my child theme.

I have been researching and I would like if you can confirm that this is the steps I should take.

This is the example function on the parent theme on file functions.php:

<?php
function parent_function() {
    // Contents for your function here.
}
add_action( 'init', 'parent_function' );
?>

To remove it on my child theme in file functions.php i should code:

<?php
function child_remove_parent_function() {
    remove_action( 'init', 'parent_function' );
}
add_action( 'wp_loaded', 'child_remove_parent_function' );
?>

Is it correct so far?

Now I would like to add my custom function to replace that one.
I am not sure how to do this. Is this the code I should write on functions.php file of my child theme?

<?php
function my_custom_function() {
    // Contents for your custom function here.
}
add_action( 'init', 'my_custom_function' );
?>

So, by the end my functions.php file on child theme should go like this?

<?php
function child_remove_parent_function() {
    remove_action( 'init', 'parent_function' );
}
add_action( 'wp_loaded', 'child_remove_parent_function' );
?>
<?php
function child_remove_parent_function() {
    remove_action( 'init', 'parent_function' );
}
add_action( 'wp_loaded', 'child_remove_parent_function' );
?>
<?php
function my_custom_function() {
    // Contents for your custom function here.
}
add_action( 'init', 'my_custom_function' );
?>

Whith this code will my custom function replace the parent function, preventing the parent function from being fire?

Thank you very much