No! The Unity Hub allows you to have multiple versions installed simultaneously. This is crucial if you are maintaining older projects that require an older engine version.
A: Not officially. Users have installed it using Windows 10 compatibility mode, but expect potential issues with USB license dongles and the simulator. Unity Pro 13.1 Download
During the installation process, you will be asked to select modules. If you are building for mobile or specific platforms, you must select these now. you must select these now.