1:Does It Damages Macbook Battery?
No, but it is better to charge it from an AC adapter than from your macbook. The more the battery in your macbook cycles the quicker it will age. Get your phone charger and charge it from there:
2: How Much Hours It Will take To Charge Power Bank 0-100%?
The depends on the current you get. I don't know because I have not tried it with your computer, but with a normal phone charger it should take 2-3 hours.
3:how long does the Power Bank Keeps Charge Energy? 2-3 Weeks Or More?
My anker batteries hold a charge for much longer. Several months at least.
4: How To Check If My Power Bank Is Rela Or Fake? I Cant Find "Seciruty 20-Digital Code" on Box Of power bank Which Anker Website Requires https://www.anker.com/verify
That's a problem, without the code it is hard to verify. Maybe look for the S/N on the battery and see if it matches the product?