1: you have the ability to create multiple viewports in UE, in UE5 theres a menu near the perspective tag, click on that and near the bottom you can see the layouts
2:you can hide actors without deleting them in the world outliner, alternatively you can toggle visible in the rendering tag
3: I dig this
4: I also like this. downloading content->create project with said content->merge to my project is a pain a lot of the times, and having a direct import would be fantastic.