Yes, we installed and registered/set up all apps and e-SIM before we left the UK. When you go to install WeChat on your phone, you are given two options- log in with Facebook, or set up a WeChat account. If you choose the latter, you get to a point where it gives you a QR code and says that someone else with WeChat has to verify you by scanning that code before you can finish setting it up. My husband was able to do this as his brother already had WeChat and could verify him. However, I understand there are limits to how many new accounts a user can verify at a time- so if they've just verified someone they can't immediately verify someone else. I was hoping once my husband had his WeChat account he could then just verify me, but we found out you can't verify a new user until you've been on WeChat a certain amount of time (I think it's three months). In the end I wound up just linking my Facebook as it seemed like the only option.
Sorry if that was a bit long, we found setting up WeChat surprisingly complicated!
Another thing to note for Amap- it's a great mapping app for getting around China. However, anytime you look up a hotel, it tries to take you to another service to give you info about booking that hotel. The challenge with this is that you need to "bind your phone number" to access that service, and it will only accept phone numbers from China and a few other countries. What this means in practice is when you are trying to look up where your hotel is to get directions back there, you get a pop up asking to "bind your phone number" before it will show you your hotel on the map and if you decline this pop up, the map won't show you where the hotel is. The way to get around this is to go to your "recently searched" and select the hotel name from there, then it will load on the map. This caused me a lot of frustration until I figured it out so I hope this helps others!