for 1)收集supporting documents
your company need advertisements for 1-6 months, of course,if they did advertisement a lot, then you don't need waste this period time.
2) 雇主申请labor certification request (Form ETA750)
your lawyer/employer file PERM EB2 or EB3 for you, it takes 2 hours if they care or 1 week.
3)Dept. of Labor's Employment and Training Admin批准或拒绝申请
it takes 3 days to 6 months depends on your case and DOL's analysts who process your case.
4)CIS(Citizenship and Immigration Service)批准移移民签证申请Form I-140 - Petition for Alien Worker
it depends on which USCIS your state belong. Now TEXAS USCIS finishes I-140 application in 1 month. California maybe 6 months.
5)6) 7)you have to watch DOS' Visa Bulletin every month to know if your priority date is available for your GC application. you are right, this step is the longest so far.........
IF congress passes the new law, then maybe you don't need wait for 5 years...but who knows...
LC and 140 related your employer, once you filed, you could not change the employer..if you change to new employer, you have to re-start each step.
But once your 140 approved and your I-485 filed for half year, you can change the employer with similar job, AC-21 will protect you and apply EAD work for other job, apply I-131 to go back home. your LC employer could not revoke/cancel your LC/140. Once your I-485 filed less than 180 days, you change the job, your emoplyer has right to revoke/cancel your LC/140 and you have to re-start it again.
I don't agree with your lawyer 不能够在公司内部跳槽. LC/GC is for future job, you should change work location inside your own company. usually once your GC is approved, you have to work for the company for half year...but I never heard USCIS would check that.
you can extend your H1b for 7th year once your LC filed over 365 days. once your 140 approved, you can get H1b extension for 3 years.
not sure which city/state is faster...now it is the same for all centers for CHINESE.