WikiSuite is a Free / Libre / Open Source software (FLOSS) enterprise suite
https://en.wikipedia.org/wiki/Free_and_open-source_software
The enterprise suite
category is for solutions for organizations that cover more than 10 traditional software categories in an integrated fashion (ex.: logins work throughout all features, etc.)
It is the most comprehensive and integrated Free / Libre / Open Source enterprise software suite ever developed
They are the individual software applications that comprise WikiSuite. Please see: Software Components
Very carefully Please see: component criteria.
No. Don't install / activate what you don't need.
Yes, it's all Free / Libre / Open Source (FLOSS). You can use different components which suits you better (legacy data, better features, etc.) Please do share why / how you did this so other can learn and make better choices for their projects.
All Software Components are released under an OSI-approved license. Please see each component page for the specific license.
No. The main use case is to set up a server (virtual or physical) for each project. But several domains can be supported as aliases, so you could have both example.org and example.com but only one user johh.smith
An alternative: Orchestrator
Please see: Projects, Roadmap and To do
Rest of content is still at https://suite.tiki.org/Tiki+Suite+FAQ