Database Attach Upgrade 2010 -> 2013 Site Collection is missing old content

Follow up: I re-ran Test-SpConentDatabase and got the following errors. How can I resolve them?

Category : SiteOrphan Error : True UpgradeBlocking : False Message : Database [WSS_Content_pg] contains a site (Id = [7554a5b9-7182-4ae9-a9ba-8b757933ee04], Url = [/sites/pg]) that is not found in the site map. Consider detach and reattach the database. Remedy : The orphaned sites could cause upgrade failures. Try detach and reattach the database which contains the orphaned sites. Restart upgrade if necessary. Locations :

Category : SiteOrphan Error : True UpgradeBlocking : False Message : Database [WSS_Content_pg] contains a site (Id = [236a8096-a426-4a56-bce7-a5586dc0f641], Url = [/sites/pg]) that is not found in the site map. Consider detach and reattach the database. Remedy : The orphaned sites could cause upgrade failures. Try detach and reattach the database which contains the orphaned sites. Restart upgrade if necessary. Locations :

Category : SiteOrphan Error : True UpgradeBlocking : False Message : Database [WSS_Content_pg] contains a site (Id = [7554a5b9-7182-4ae9-a9ba-8b757933ee04], Url = [/sites/pg]) whose url is already used by a different site, in database (Id = [9b8dafcd-29de-4a4b-bc91-689a4ed5fc3a], name = [WSS_Content_pg]), in the same web application. Consider deleting one of the sites which have conflicting urls. Remedy : The orphaned sites could cause upgrade failures. Try detach and reattach the database which contains the orphaned sites. Restart upgrade if necessary. Locations :

Category : SiteOrphan Error : True UpgradeBlocking : False Message : Database [WSS_Content_pg] contains a site (Id = [236a8096-a426-4a56-bce7-a5586dc0f641], Url = [/sites/pg]) whose url is already used by a different site, in database (Id = [9b8dafcd-29de-4a4b-bc91-689a4ed5fc3a], name = [WSS_Content_pg]), in the same web application. Consider deleting one of the sites which have conflicting urls. Remedy : The orphaned sites could cause upgrade failures. Try detach and reattach the database which contains the orphaned sites. Restart upgrade if necessary. Locations :

Category : MissingSetupFile Error : True UpgradeBlocking : False Message : File [Features\ReportServer\ReportViewer.dwp] is referenced [2] times in the database [WSS_Content_pg], but exists only under Microsoft SharePoint Foundation 2010 setup folder. Consider upgrading the feature/solution which contains this file to the latest version. Remedy : One or more setup files are referenced in the database [WSS_Content_pg], but are not installed on the current farm. Please install any feature or solution which contains these files. Locations :

Category : Configuration Error : False UpgradeBlocking : False Message : The [SharePoint - 80] web application is configured with claims authentication mode however the content database you are trying to attach is intended to be used against a windows classic authentication mode. Remedy : There is an inconsistency between the authentication mode of target web application and the source web application. Ensure that the authentication mode setting in upgraded web application is the same as what you had in previous SharePoint 2010 web application. Refer to the link "http://go.microsoft.com/fwlink/?LinkId=236865" for more information. Locations :

/r/sharepoint Thread