We haven't announced a release date yet, as the work is being done off-hours by a small team. We hope to share more info as we get closer to completion.
It is an update rather than a remaster, but will be a new entry in your Steam library, and free for those who already own it on Steam. That way you will still have access to the original version with your existing saves and boss characters if you need them.
It was announced in August that we are in development on a new Saints Row game. We don't have any other information or details to share beyond that at this time.
Other than resolution support for modern systems, there are no plans for any visual enhancements like ray tracing. This update is for performance, bug fixing, multiplayer support, and DLC content.
We didn't lose anything. The port was done by a different studio and then lost in the old THQ bankruptcy auction. We were able to finally track down from a source that wishes to remain anonymous.