Yes, online filing can be done in all cases as far as I know as thats what the company that has offered me a job told me.
Yes the priority date is correct. I worked for a company for 7 years. They had started my green card process and labor got approved in 2006-2007 after a huge delay. Then they appied for I140 but due to economy was let go. So joined this new company. Worked for them for 3 months. Meanwhile old companies I140 went through. Now on H4 visa. Waiting for green card process to go through.
So everything that I had up there is valid:-)