Yes there is mossy rock and icy rock in ORAS
It is in Petalburg Woods.In the north-east of Petalburg Woods, behind a Cut tree, you will find a small moss covered rock in the absolute corner.
It is in Shoal Cave.In the absolute bottom floor of the Shoal Cave, you will find a small moss covered rock in the middle. This area is only available for short times every day. It is available when the tide is out between 03:00-09:00 and 15:00-21:00 every day. In all other times, it will not be accessible.