2) I am not quite into 8.0 but I think .net Framework 4.8 should definitly be compatible, since it can be installed on Vista too. I just think you have to install the one that was offered to Server 2012 R1, by modifying the installer
3) I actually used IE as my main browser till at least the end of 2017/early 2018, but I wouldn't waiste my time and patience with endlessly patching that Dinosaur. Back in the days, I desperatly tried to find ways in how to backport IE10 to Vista, but even I noticed that it won't change much. Websites will still not render properly and you can't access modern media sites, like Spotify. I mean IE11 can be sideloaded, there was a way described in this forum, but I don't think it is worth doing. Go with Edge if you really want to have IE's legacy living up, but otherwise Chrome, Opera or Firefox.