Stunning display Ian! Do any of them have a favorable scent in your opinion? The short answer is no. I find that only a few of the yellow flowers have any scent beyond a general "warm pollen" aroma, and they are usually quite sweet, honey perhaps. L. otzeniana is pretty good for that, but...

Have you got any other stocks. Seems like saving the top should take priority over experimenting with the bottom. Or just take it off and wait for another stock, or even wait for it to put down its own roots. Then experiment with the stock

Here's L. otzeniana 'Aquamarine' with the summer sun long gone. Getting greener by the day...

There are white flowers, too. This is L. karasmontana ssp bella and ssp karasmontana.

Its pretty late in the season for all those yellow flowers, and this L. hermetica hasn't even started.

Not much sign of a white eye on this L. bromfieldii.

L. hookeri doesn't officially have yellow flowers with a white centre but this plant does.

Here's a normal coloured one, L. olivacea var nebrownii.

First flower on this Lithops anyway. It is over ten years old, so that is quite a wait. L. olivacea 'Red Olive' officially has yellow flowers with a white centre, but you can't see much of the white eye on this newly-open flower.

I'm guessing the "white flakes" are the large corked patches? They would be caused by poor growing conditions or a pest. The plants do look thirsty. That could be due to underwatering, but more commonly is due to root loss after overwatering or because of an unsuitable soil. Always worth c...

That's tall! Is it actually a Tanquana? Only time will tell, but I've never seen one that tall. If it is a Tanquana then more light won't hurt. If it isn't then I guess it doesn't really matter if you fry it

Monilaria is the only obligate summer-dormant species that I can see, but pretty much all of them will go dormant when it is very hot. Then you'll need to avoid deep watering and if necessary spray regularly to stop them from drying up completely. They could get pretty ugly. Things like the Delosper...

Reduce? I stopped ages ago. It has been a particularly warm autumn, but then its only England so hardly baking. Humidity is very high now and I can't imagine watering anything except the most obvious winter growers.

Look at the roots, pick a pot only slightly larger, as best you can given the size of the top part. You can repot again next year, or perhaps the year after, if they rapidly outgrow that pot.

The Anacampseros has flowered already. You may have blinked and missed it, or it might not even have opened. They need a good amount of heat or very strong sun to open them up. What you have now is fruit.