I read on the tear sheet that the ac lite can only do af/at PoE in, but on the quick start guide it says passive also works. Does passive work? Can I power this device with the hex s?

wsAP ac lite can be powered with passive poe.
However, there is a recend thread on the forum, about hEX S having some poe output problems to hAP ac2:

viewtopic.php?f=2&t=138036

Power consumption for wsAP ac lite is lower than for hAP ac2 (10W and 15W respectively), and on 24V it will be less than 0.5A, so it can be a non issue in your case. But you should be aware anyway.