Have u ever read the definition of bounce rate given by the Google itself in Google Analytics?
As per the Google, "Bounce Rate is the percentage of single-page visits (i.e. visits in which the person left your site from the entrance page without interacting with the page)."
Lower bounce rate or higher bounce rate has no concern with your ranking but yes, how much time visitor spends on your site or page is matters. If visitor spends adequate time on a page and left the site then it won't consider as bad thing for search engine ranking. Yes, Average session duration and Page/session are two most important factors you should keep in mind while analysing your website performance..
For FreePriceCompare website, we applied all standard practice for speeding up the website like image compress, simplify the scripts and other things. Server response plays an important role in order to speed up the website so please make sure that you are on the high-speed server.
There are number of ways to build links, all techniques are good but one has to follow the best practice of each. Few guys are saying the blog commenting is dead. I never feel that. I regularly comment on relevant niche blogs and news and also get quality backlinks. I never cross the line of relevancy and my comment always adds value to the article otherwise I keep myself away from commenting. I have done around 100 comments for https://freepricecompare.com
You have to convince him for changing the link, no other option you have. Yes the issue with any blog post then you can write another blog with your company's website and quality content and publish it in the same website, so there are chances of getting your blog first instead of his blog.