Can i file H1B extention before i94 expiry, then amendment or transfer after i94 expiry?

I am working in company A.

My project will be over by Dec 31st 2019. I94 is valid till 31st Jan 2020.
My current company took my documents for extension, but not filed till now.

In case they file my extension around december end, I will get reciept copy for my extension.

After 1st Jan if they file my amendment for new location and new project , is it allowed before my H1B extension renewal? I am in confusion.

When they do amendment, they can again file my extesion with amendment?

Please advise me on this, In case if I try for new company for H1B transfer before what date I need to move on?

Best regards

You can file extension before i94 expiry.
Once extension has been filed, amendment can be filed anytime.

You should file transfer before i94 expiry to avoid bridge risks.