So, there is not really any need for you to add any information to the BIM or modify it in any way whatsoever.
All you need to do is visualise your data coming from an external source in the BIM.
Maybe you should consider basing your work on Autodesk Forge instead of the Revit API:
https://forge.autodesk.com/
That will give you access to far more models, since the BIM can come from any CAD seed source file you like, in any format you like, not just RVT.
Furthermore, the existing open source visualisation tools and libraries available for the web browser are probably more powerful and better adapted to your visualisation requirements than the Revit API.
Please research by yourself about realtime data visualisation in BIM models in the Forge viewer, e.g., searching for 'data visualisation BIM model Autodesk Forge viewer':
https://duckduckgo.com/?q=data+visualisation+BIM+model+Autodesk+Forge+viewer
If you need more help on Forge, please search for answers on StackOverflow first, and, if still needed, raise your questions through the standard Forge help channels:
https://forge.autodesk.com/en/support/get-help