Hi, as regards point 1 trying to upload an image and hope it works: you see track name on line 1, artist and performer on line and file format on line 3. On the side time elapsed and a circle representing what remains. It’s brighter than appears on the photo but if you are sitting a few meters away, font is rather small. No scrolling but maybe that can be set up so if you are relying on the Lumin display to know what exactly is playing, of limited help (here it’s playing a piece of classical music and you cannot therefore which of the 5 movements is playing).
As regards point 2, I am sure Peter will give you a fuller answer but I would have thought that you can simply set max resolution in the Roon device settings so that it automatically downsamples or converts as necessary. Alternatively you can do that in the Lumin app or set conversion up or downsampling in either Roon DSP settings or the Lumin app. I believe Lumin would recommend using Roon if possible.
Peter should know regarding compatibility. My U1 mini feeds into the USB input of a Meridian 818.3 and as a streamer, it has been rock solid and the sound is great. I say this after over 18 months of regular usage. There are cheaper options but having tried the Pro-Ject Stream Ultra S2 the last few days for my headphone setup (and not to replace the U1 mini which is in my main speaker set up), that unit has way more bugs (can’t stream native DSD via Roon) and no one at the dealer or distributor could figure out the bug which seems long-standing (hence didn’t buy that unit) whereas Lumin support on this forum is 5 star.
Hope that helps.