you are thinking this is more delicate than it actually is and there really is no reason whatsoever to not transfer the rock now, the sooner the better.
you could transfer everything into the new tank and monitor the levels and do partial changes if needed.
As long as you don't add any new livestock and reduce feeding for about a week, chances are it will be fine. You will see a brief minor elevation in levels, but I imagine no more than a few days.
I have done this many, many times with success.
I transferred the entire contents of a 30 gallon into my 50 and experienced a "cycle" of about 30 hours, if that and that was about 7 fish, lots of inverts.
I threw together a 10 gallon by using rock and filter media from my 50, dumped a trigger and two eels in there and never saw so much as a blip in readings.
If you do transfer everything, rinse the sand well in the old tank water to remove as much detritus as possible, but it will retain bacteria to help seed the new tank.
OR you could leave the filtration in place on the 10 gallon, leave the critters in there and move the rock to the new tank and that would help get the new tank started and shorten the cycle time.
a single shrimp and coral are not going to produce so much waste that it would be problem while the tank settles and adjusts.
just transfer everything into the new tank in a few days when you know all is good on the new setup.
No need to deal with rotting shrimp in the tank when you already have the needed bacteria and stuff in the ten gallon.
telling you to cycle from scratch is poor advice IMHO