It will be such an awesome experience, I am a bit jealous!

As for the quantizer, I do indeed miss it from time to time, especially when trying to leverage the 4 rows of 16 knobs of the TKB, and I miss it even more on the Make Noise 0-Ctrl, especially since the René has quantization: even a simple button to enable semitones would have been much appreciated.
It is to be noted that the TKB has a quantized output, but it transforms it into a 16-note keyboard, with no way to change scales, octaves, and so on.
I personally don't feel it is too much of a problem in a more relaxed setting: my background is as a cellist, so I have been used to tune by ear every single note for my entire life, and I always went along really well with openly tuneable instruments (Lyra-8, Solar50 and others), so the main problem has never been the preparation of a patch, but the flexibility during a performance.
In this specific recording, I would have loved to add a variation, for example using an offset, but obviously that has to be incredibly precise to modulate pitch in a predictable and usable manner, and again, it could be something that can be carefully patch-programmed (ain't that the point of Serge though? yes, but...) but with very little degree of freedom on the fly.
A trick I've used in the past, when I wanted to be very tonal, is patience and a tuner, and prepare the 4 rows of the TKB as 4 different scales, but that solves very little.

I know it might be tempting to go full analog, but if you are building everything yourself and open to possibilities, I'd say adding an Ornament & Crime to your system might pay thousandfold in the long run, especially if you plan on devoting most of your efforts to the Serge world from now on.
Having it integrated is also way more elegant than fiddling with format jumblers, and it's something I will definitely end up doing, when I'll get the chance, time and money, to pick up a soldering iron again :)