Upgrade Path Questions

I am looking for suggestions, steps to update/replace one site with another.

scenario is as follows:

www.domain1.com : running OC 3.0.2.0 20 categories, 100 products.
www.domain2.com : running OC 3.0.3.8, 10 categories, 50 products.
Each domain is running its own unique webdomain, both running different themes.

I want to replace domain1 with domain2 (webfiles, programming, data, images).. so that domain2 is now the website (domain1).

questions:
1. will backup and restore in OC accomplish everything I am trying to do?
2. will I need to make adjustments following restore to the config.php files? to other settings in the oc admin?
3. what happens to the web pages/images of the 10 categories and 50 products that will no longer be needed with the new website. are they deleted during restore? or ??
4. how can I get 301s done on those pages that are no longer needed.
5. please mention any other pitfalls you think i have missed.

thanks for the assistance.
Robert

There are no 3.0.2 nor 3.0.8.0 versions of OpenCart!

versions corrected to read:

domain 1: 3.0.2.0
and
domain 2: 3.0.3.8