minamousa

It's the second one. From the date of the issuance of the visa, you have 6 months to enter.
If you enter the day after it's issued, you have 90 days from entry to the US to marry (about 3 months after issuance).
If you enter the day before it expires (6 months later), you have 90 days from entry to the US to marry (up to 9 months after issuance).
If you enter on any day in between, you have 90 days from entry to the US to marry.
As you can see, the expiration of the visa only has to do with the entry to the US. Once entered, a different clock (the I-94 expiration date) starts, and it is always 90 days. I can see how it can be confusing, especially if the correct vocabulary isn't used.

2. Once approved the K1 visa is valid for 6mths ( to get into the usa) and an additional 3 mths (90 days) to get married once in the usa

K1 is valid usually for 6 months from date of issue or as specified in the "Valid until field". Note there is no requirement that you must go to the USA within 3 months or 90 days, only requirement is once you are in the USA you must get married within 90 days and hopefully until then your K-1 is valid too. If not, you can just file for AOS and the noa you receive in lieu of AOS protects your status.

You need to call NVC to get the case number and IIN. Thereafter, check your case status at https://ceac.state.gov/ceacstattracker/status.aspx by using the case number to figure out where your file is at. If it says "Ready", you can try to call the embassy in Egypt to confirm their receipt of your case file and maybe ask them about the Packet 3.
 
Whilst you can complete the DS-160 first, you'll need to either have the Packet 3 or embassy's instructions before scheduling for an interview. Not sure about your embassy but some might just assign you a date and time, leaving you no flexibility on choosing your preferred date.