I'm a non-resident alien working in the US as a H1B visa holder. I'm beneficiary of an approved I-140. My current I-94 expired on Oct 2017. An H1 extension for me and H4 extension for my spouse has been filed and not yet approved. Can I apply for an H4 EAD for my spouse now - before I receive approval for my H1 / my spouse's H4 extension? If so, till what date will the EAD be valid?