You can set up access just to their module directory in cpanel. I have never tried to set a document root for sftp on cloudways, but I am sure you can.
It is. Once someone has sftp they can get the mysql access from looking at the settings file.
Trusting your developer or hiring a developer you trust is the best practice.
Can you test with the latest module and see if the issue is still present? The issue cannot be fixed one off in an old module, it would need to be fixed in the latest version of the module if it still exists.
Compatibility is one of our main focuses. We are always looking at ways to add new features and improve the core without breaking modules and compatibility.
Well there are ones, we use a Mandrill one for all of our emails, but they are paid services. I don't know anyone that allows third party smtp for free is what I meant.
This is one main reason we use 3rd party SMTP servers on a lot of sites. You can see the emails without having them sent to you. You can also see the delivery and open status as well.
Also check the status in the back office for which template is sent, then look in the /themes/transformer/emails/en directory to make sure the template is on your server.
If there is white space around the image it will leave the same ratio of white space. Disabling the images will make your site stop showing up images of those size, they are not automatically replaced with another image size.