In my opinion the condition is in a mild and reversible stage.It has been caused probably due to inadeqaute hygiene maintenance leading to accumulation of plaque and calculus.

Go for scaling and polishing

This photograph shows in some area interdental papilla (interdental gingiva )becomes swollen and some interdental area space may occur(the cause of this interdental space is due to bone recession. One  lost it  not come back  again naturaly. The cause of this gingal bilging is calculus deposit around tooth gums area. This deposit gracturaly resorb the bone around teeth and swollen gums.

Yes according to the picture you've put, it is a possibility that your gums can fill up the space.

Yes definitely it can be corrected. Proper cleaning is required first. And then your gums can be filled naturally. It's a painless and short  procedure.

Yes

According picture you have gap between teeth. That inderdental gap can be filled naturally with gums . Can Connect through chat box.

Yes your gums can be corrected.... Firstly you need a good scaling of your teeth.... And subsequently according to the condition of teeth small periodontal surgery can be performed to make your teeth look good

Yes it may grow back. You would require a thorough clean up. And later, you can massage your gums in the upward direction. Make sure you maintain good oral hygiene after cleaning .