1 You can use approved labor certification if your Education Exp was the same before the date that LC was filed. You cannot use Experience gained through H1 with the current employer.
2. Get the original approved LC that was sent by DOL to Lawyer or employer and make 2-3 copies from that original, then meet some good lawyer, show your Educational evaluation, past work experience letters, resume. Then he will evaluate looking at the approved LC and your education, Skills and experience if you are eligible to use it. It is not easy to make guess because nobody in this forum has seen the LC that is with your employer. Most important part to look is on ETA750A Form in column 13, 14, and 15
3 if the lawyer is confident that your education match with the LC and you had these skills, required education before LC was filed then he will advice you.
4 For I-140 filing you need all past exp letters, education evaluations, degree certificates, transcripts and approved LC. I-140 has to be filed by Employer NOT by you
5 If lawyer advises that you are eligible for Labor substitution he will provide you list of documents for I-140 and I-485 filing. You can file I-140 and I-485 concurrently.
You can visit
www.immihelp.com and find the list of documents under AOS or I-140 filing