1. At the first page of the Quick Template it says "New" and "Drafts". There is also buttons like "Next" and "Submit". Can these be translated to local language with a Basic license?
-- The builtin strings within the Template are already translated for users to use. Just install the app on your device and change the locale of your phone. Run the app you will see the translated strings. However, any user provided or custom strings requires translation by user and would need Standard AppStudio license.
2. When a submission is done, it says "Thank you Submitted Successfully". Can this be translated to local language with a basic license?
--- Currently, it is not translated. But you can use your own string based on any language. However, you would have to upload the app to your Org account before you can do build, which requires Standard AppStudio license.
3. Can we change the basemap in the quick report template from the standard topographic map to another standard esri basemap with a basic license?
--- No, but if you have Standard AppStudio license you can change the configuration such as basemaps and do a build.
4. Can we edit the color schemes in the app with a basic license?
--- No, You need standard license to do that
5. Can we add/edit the text in the "About" section in the quick report template with a basic license?
--- No, You need standard license to do that
In short, any of the above changes require AppStudio Desktop to upload and build the app which requires Standard AppStudio license. With Basic license you can only build the templates with the configuration available on the AppStudio website. To learn more about it see following help
AppStudio for ArcGIS license options—AppStudio for ArcGIS | ArcGIS
Another useful resource to learn the difference between AppStudio Basic and Standard is shown below
Frequently asked questions—AppStudio for ArcGIS | ArcGIS
Nakul