On the homepage, is there a way to change the Shop Latest Items number from 3 to something else?
Yes you can change this yourself. Go to the map template-parts/homepage/ and locate the file called: content-homepage-shop-sale.php. Open that file and you'll see this shortcode:
<?php echo do_shortcode( '[sale_products per_page="3" columns="3"]' ); ?>
You can change the per_page to a higher number and you can also change the columns.
If you have any further questions do not hestiate to ask them! Also if you happen to have some spare time, please consider rating my theme on ThemeForest (by using the stars next to my item in your Downloads page). I would very much appreciate it!!