We are still in the process of releasing our App support for the 2-way switching setup, so the feature is not currently available on our App. We will post an update when it becomes available!
Yes, all Den Light Switches can be used in a 2-way setup. This means that two switches can control one lighting circuit. For example, in your hallway, you might have one light at the top of the stairs which you wish to control from both upstairs and downstairs.
If you replace only 1 switch in a 2-way scenario you would still be able to manually operate that light from either switch, however, we highly recommend using Den switches at both ends. This is because if you replace only one of the switches, the Den App will show the incorrect state some of the time. This is because it won't be able to tell the state of the non-Den switch.
Den Dimmer switches are still in development but we intend for them to be 2-way too. However, details are subject to change until the product is launched.