I use SmartTiles instead of widgets. It is a webpage and provides all the quick functionality you may want to have in one location. I believe there may be other solutions, but I have all my automations on motion triggers and rarely use the app.
Not really. I rarely pull my ST hub out to add devices. It is recommended because it remove the possibility of interference. I recommend going from closest devices to further devices from your hub. The minimote will not help with this since the device is searching from the hub. You do need to exclude from Vera before the add to Smartthings.
Explore community supported smart apps. Nest-Manager for Nest and Lock Code manager are awesome (links below). They are a little confusing to install at first, but once you get the hang of the ide its super easy. Nest-Manager has good step by step instructions to get you started.
Logitech is a supported smartapp you can add under marketplace in the app.
Links!
This community is top notch, you will get your answers here.