That would depend very much on what kind of app you would be running on it. If it's an app for 10 users with 3 different forms then you could use almost any machine. I suggest talking this over with your contact in Mendix as there is no generic answer to this question. SQL Server should be at least 2005 though, with at least Microsoft 2003 server.
Well it depends entirely on your requirement. Like for instance I have two servers one is small apps and the other is one is for an ecommerce app which are considered as the big apps. So, I have two different types of aws web hosting servers for both of the apps that are set to different configurations.
You can check the servers for yourself by clicking on the link mentioned below: cloudways.com/en/amazon-cloud-hosting.php
1 server which is set on the conventional blog consists of:
While the other servers consists of which is set for e-commerce app consists of:
and they both are working fine for me. As, I have choosed the servers according to the requirements of my app.