Hello,
My Name is Raviprasad, Cloud Systems Administrator from India. I've 4+ years of experience in the Amazon Web Services, Google Cloud and Digital Ocean platforms. Currently I'm managing 12+ Apache/nginx based production web servers in the AWS cloud for one of my customer.
For your requirement, I suggest you to use Nginx web server as a reverse proxy and SSL terminator. So all your domain names and related SSL certificates will be configured within this Nginx host and backend virtual servers will be linked using the private IP addresses. So all the web requests will be initially reach to the Nginx host and from there, based on the domain name, it'll be routed to the correct back-end virtual server. All your websites will have the same IP address and also Nginx will boost the site performance using cache system. But performance improvement also depends on the server hardware.
For protecting your websites from well known internet attacks, I suggest you to use Cloudflare free plan. I can give more information upon request.
Please have a look at my freelancer profile to know more about my skills and past ratings. Feel free to contact if you have any questions.
Looking forward to work on your project.
Thank you.