1) Deployment center is no longer needed since version 7.5
2) Backup / restore for DB, and MSDeploy for files (usually it's a part of continuous integration process). You don't have to copy system files.
3) From my experience, the best thing is to re-build the search index manually. Search index is usually stored in App_Data\Index. Check episerver.search.indexingservice section in web.config
I have few question related to deployment.
1) Where can I download deployment center setup ?
2) Currently we are buidling an application using EPiserver 8. I would like to know the best practice for moving files from dev to staging to live. Staging and live don't have Visutal studio to install package through nuget. I have read that copying site root files which is created after installing nuget cmd is enough. While moving my dev site root files to staging server, does it require any other files(like system files) need to be copied from my dev to staging ?
3) In case if I installed search in my dev, what are the files should be copied from dev apart from files inside site root ?