my wife will get the H4 visa and a few months later she will get the EAD, can she stay in H4 status and work using the EAD? or she must switch to H1B1?
I don't have personal experience in this, but I know that a H4 visa holders are not allowed to take up employment in US unless and until the person converts H4 to H1.
How will you wife get EAD? Is she sponsored for GC by family member?
As I said, I don't know much, but here is what I found as an answer from a lawyer to a similar question (question was posted by H4): 'If your spouse is in the last stage of the green card process (AOS) and you are still maintaining your H-4 status, then and only then can you apply for employment authorization and start working, but this is not because you are still in H-4 status but because you have a pending AOS application.'
Maybe somebody else can help you more. Did you ask that question your employer's lawyer or whoever is doing the papers on their side?