1. Where can we get layout databases (GDSII stream) which are free IP , that can uses for research, study and evaluation? Does any foundry, EDA firms or ARM provide such IP? Anywhere from 90nm --> 45nm.
2. Where can I download or get process development kit which is open for public? Let’s say I need some design rules, parasitic RC info for extraction, timing info/arcs, etc.
There's much more information to be found on the Mosis website.
You can also work with e.g. Europractice/IMEC on the same kind of info, but generally you need to sign an NDA in advance (which shouldn't be an issue if you're serious about making an IC).