Leica did release the SL with 4K, L-log and 4:2:2 output in November 2015 which makes decent images. Regardless, they are still far behind because their system is highly impractical for video.
I saw this video and found it interesting but did feel that something was amiss. I know that some people love to bump the contrast and saturation but that doesn't always produce a desirable result. I totally agree with what you say about the current style of color grading being flat. It's mostly just a trend in my opinion.
I think one of the best ways will be to use your lowpass filter or cut the high frequencies in eq. That'll give you a sense of distance as high frequencies don't travel through objects as well. Be careful not to over-do it though. Also just plain-old turning down the volume on those individual audio feeds. In the case of the record player, if it's in the corner of the room just turn it down a little, maybe apply a tiny bit of lowpass and pan it accordingly.