How to get the total number of comment of a channel using YouTube Data API

I am using YouTube Data API and can get subscriber count, view count etc. by using the statistics parameter. I am aware that statistics cannot be used to get total likeCount and commentCount for a channel. But the API allows to get the playlist videos using contentDetails.relatedPlaylists.uploads.

So, my questions are

1. How can I use the contentDetails.relatedPlaylists.uploads to fetch individual videos' likes and comments and append them into a JS variable?
2. I used contentDetails.relatedPlaylists.uploads.items.likeCount to get the total likes of playlist individual video. But that seems to be incorrect. What is the correct term to get the total likes of a playlist individual video?