Thank you for using Bitnami.
We have different guides in our documentation that explains how to configure a certificate in your application. Depending on if you want to use Let's Encrypt or not, you will need to follow one of these guides
Our documentation also has a guide to configure Apache to redirect all the requests to your domain, that way no matter if you use the IP or the domain, it will always show the domain in the browser bar.
This depends on the machine specifications, in this case, I suggest you ask in the official forum of the application to know more about the requirements the application needs to work properly. Then you can resize the server easily by following this guide
The Ghost forum is here: https://forum.ghost.org/
Where did you obtain this error? Can you share a screenshot of it?
We provide technical support in this forum. Our team is actively monitoring it and will be glad to help you here, usually within a business day, and the whole community will benefit from your contribution.
Let us know if you have any other question.