Depends on labor cert.
> How long would it take for a fresh GC application in the EB2 category? what would be the range for labor, I-140, 485 to get cleared? which is the biggest stumbling block?
First hurdle to clear is the Labor cert. or RIR process takes anywhere from 6+ mths to 1+ year. I-140 too can take upto a year, 485 depends whether dates are current in future. This is all future projections and there is no way to tell if some new laws are introduced to speed up or slow down the whole GC process.
> if one has multiple H1-B\'s and is working fulltime for one one employer, can the other company process his/her GC? if yes, how does that work out towards the end of the processing cycle, typically at the time of AOS, fingerprinting, etc?
This is possible in certain cases yes, there are many posts of these nature, check archived discussions. Normally a person would be expected to be working for the company that is primararily sponsoring H1, Labor, I-140, 485 etc. There should be no impact on finger printing or AOS but it depends on how the immigration officers interpret the entire case at various steps of the process. The best approach should be to keep things as simple as possible.
> which is better option under prevailing circumstances CP or AOS? especially after 9/11. under what circumstances would one be a better bet than the other?
CP has a faster turn around than AOS, again you never know. After a few months the tables could very well be turned upside down depending on INS policies and procedures in place in near and distant future.
> from a GC sponsor perspective, is filing a H1-B a prerequisite for processing someone\'s GC? if not, what are the modalities of taking this route?
GC can be sponsored by other methods too example family based. H1-B is sponsorship through work/employer.
> Can one pursue ones GC through ones own lawyer as opposed to the company lawyer? is this recommended? would the company take offence? is this significantly faster? by what percentage? what are the typical fees that lawyers charge?
There are no real statistics to indicate which method is faster. Any experienced lawyer either a company appointed or private firm could be equally good/faster. Lawyers are there to look after client interests, emotions, offence and other personal preferences should not play a part. They are out there to make a living first. The entire GC process can cost anywhere from a couple of thousand $ to upwards.
> currently how long is taking for a GC to be processed if filed from california?
Varies from case to case, the range is 2-4 years to 4-6 years for family based.