2)but still not received the hard copy of the same.
my h4 extension is also in process, can i need to withdraw the same or need to wait for hard copy.
how long it take to receive duplicate copy of the same
5)before receiving the hard copy of i797, can we join project.
Your attorney should follow-up w/ USCIS to get the hard copy. SLA is 30 days and your case is too close to the deadline of the same.
When approving the H-1 in PP, they must have emailed the details like I-94 number etc. From the same, if employer/attorney can gather that H-1 was approved w/ COS, then you can rely on it and withdraw your H-4 extension.
Your employer has to complete I-9 requirements before hiring you. Check w/ them when they can and what docs they need. Based on that you can join them.