Sure, why not? You can rank every page on your site for a different keyword(s).

I think its effective the inner page must have a content but not similar from your home page, It must be a related content that are useful and informative to the readers.

Yes, you should backlink your inner pages to create deep links to your site. It will help you out a ton in the credibility area. Also, make sure to link you inner pages together all over your site, as backlinks from your site also count as well. Control your backlinks where you can!

Yes, you can build links to your inner pages. Just don't forget the importance of your homepage.

Building backlinks to inner pages not only helps them to rank, it also helps your main page. Every page on your site should have a link to your main page, so in essence you are building both.

yes, if you will optimize the inner page, you will get inner page in ranking

Definitely, sometimes it will give you a double-listing in G. I've actually got a quintuple-listing for one of my niche sites from sending a few backlinks to the inner pages.