I just want to know the following
1. The gen 3 jimny starts from which year and ends when?
2. Whether the 1.3 gen 3 jimny has a 3 speed auto or 4 speed auto transmission? And what about the 660cc?
3. And whether the 4x4 transmission has a mechanical lever shift or electrical button shift? Talking about the gen 3 jimny only.
4. Experience of driving the auto? Does it have enough power in difficult terrains?
Regards

When the 3rd gen showed up depends on your market.  The Wikipedia page has been updated pretty well:

https://en.wikipedia.org/wiki/Suzuki_Jimny

Still annoyed they got rid of the old SJ page...

In low range your going to have enough power, but the auto is always likely to be a bit gutless compared to the manual.  But you should look up some automotive reviews since they were not sold in the North American market.