I don't grow many cacti but I think your Astrophytum is probably semi or fully dormant right now while your Cono should be in full growth. You can remove the Cono and give it a soak if you're brave or remove the Astro and the Lithops and then give the Cono a drenching. It looks like it can still plump up. If you can get it plump again, it will sheath over in the Summer and with a well-timed watering in early Winter, fresh growth will emerge from the papery sheath.

The Titanopsis and the Cono are in full growth mode right now while your Lithops are growing but very slowly, needing less water. Those are some very nice plants, by the way.

Thank you, I will take out the cono and wet it and repot them separately.