1. Well there is a variable for that in project folder/src/services/config.ts .
refer : http://prntscr.com/i807q8
2. Well please list the pages where you are getting these issues ?
3. That is intro page and those images are svg images .you can simply delete the all content withing the svg tag and then simply place the img tag to replace the images.you can find intro page in your project/src/pages/intro/intro.html .
edit it like html file .
4. Well its irrelevant to change the favicon because its a mobile app and it does not have any favicons .
You would need app icon and splash image in your app.
5. you need to configure it refer : https://ionicframework.com/docs/native/google-plus/
6. please share the ids of these particular course categories with me then I can provide you code for it .