There are a lot of questions in this...question.
"Roles and Features" exists to install roles and features that are part of the base Windows Server OS rather than having everything pre-installed for you. It's not meant for 3rd party or open source software.
Installing 3rd party and open source software is perfectly fine even if it replaces a feature provided in the OS like a web server. There are also a lot of different ways to automate software installation in Windows but that is too broad a topic for this question. If you need more help in this area, make a separate question with more specifics.
Yes, running each service as a dedicated "least privilege" account is highly recommended. You may need to install things as an admin user, but you should never need to run them as an admin user unless the software is very poorly written.
If this is a server intended to be running in a "headless" fashion, yes. You should make every attempt to get things running as native Windows services. Even software that doesn't natively support running as a service can be made to run as a service. Though again, specifics will require a separate question.
The most important "Do" of Windows server administration is to keep it patched. The nature of security patches these days is that they are often being exploited in the wild by the time they hit Windows update. And patches often require reboots. Design your services to expect reboots and be able to recover from them automatically. There are multiple ways to make patch reboots predictable such that you can warn users in advance about a maintenance window.
Some good practice "Don't"s. Don't turn off UAC. Don't turn off the firewall. Don't use your server for casual web browsing. Modern Windows servers do a pretty good job at being secure by default. But there are a lot of ways you can choose to make yourself less secure.