H4 visa and H4 EAD

I am currently on H4 visa and my husband on H1B both our visas expire in Dec 2022. My husband has got approved i140 and his company applying for H1b extension.
Q1) Can I apply for H4 ead before husband’s H1B gets approved just with receipt number right after his company files it?
Q2) Will my H4 Ead process starts once husband’s H1b is approved or it wont until I file i539 and get it approved?
Q3) Once my husband gets i797 approved, can I travel to India and directly get stamped while my h4 EAD is filed and pending. So this way I wont be filing i539 but filing DS 160 and getting stamped directly with husband’s approved i797.
Kindly need guidance. Thank you

Yes. Ideally you should file with the H1B and H4 extension of status.

Primary H1B and H4 needs to be in valid status for H4 EAD approval.

Yes, provided you get visa appointment. Another solution is once your spouse H1B is approved and before your H4 I-94 expires, you can visit Mexico or Canada border and the CBP may extend your I-94.

Thank you. Can I apply for both H4 extension and H4 EAD online?

Can I file H4(i539) and H4 ead(i765) both online?
Can you please share sample filled forms of the above mentioned forms for filing reference.