Yes, these models do include a FM tuner. Do note on the RCX-1500, RDG-1520 and RT-09, that while the FM tuner does not draw its signal from the internet, it is a part of the internet radio module therefore will not start if one of the USB dongles is not physically connected to the unit.

Yes! 3D video is a supported feature for these models. 

Do note for models RSP-1570, RSX-1550 and RSX-1560 that a software update may be required to enable 3D video support if they are not currently running the latest version.

The HDMI switching hardware in these Rotel models predates 4K technology and so unfortunately these Rotel products cannot pass 4K video signals and cannot be updated to support this.

If you wish to use 4K video with these models, consider running the HDMI video directly from your source device to the TV, then if the source device offers dual HDMI outputs you can run a second HDMI connection to the Rotel processor for audio, or if this is not an option use a different connection such as Optical for audio.

The RDV-1093, RDV-1092, RDV-1080, RDV-1060, RDV-1050, and RDV-1045 will play high-resolution audio from any DVD-Audio discs.

DVD-Audio discs are also compatible with non-DVD-Audio players such as RDV-995 and RDV-985, however when playing a DVD-Audio disc on these player without DVD-Audio decoding capabilities there will only be a standard Dolby Digital or dts 5.1 audio output, not the high-resolution stereo or multichannel audio.