Update Visual Composer and debug website

We are trying to update our home page of our website, an e-commerce site, a Word Press site. Replace 8 images/buttons. However Visual Composer is not working. We have a concern that updating it will have a domino effect and bring down other functionality. This is the 1st urgent task.

Then there are many plugins active and in need of updates, and the versions that we have on are very old for some of those plugins too - meaning updating one of them may fix one issue but may create other problems and could crash the whole site.

So we need quite a lot of development and de-bugging carried out to fix the website as it is.

It may require a full website backup to be taken beforehand because it may be risky to update in it's current state.