Just to complete the addition of the shallow water combo: enemies can't walk on it. This also saves the trouble of adding rippling water around enemies.
Implementing this feature shouldn't be a big problem, because the code for this is already present in the pit combo's (enemies can't walk on that either).
BTW, the 'enemies don't walk on water' also happens in LttP, this can be best seen in the castle sewers when the mice don't run on the water.
Here's an idea that should help: Enemies can't walk (but Link can) flag. Sure, this could mean a complete change, but we probably need it. This flag was originally in the future Ideas, but I just wanted to bring that up. This could help making custom bosses or a "Enemies avoid SWater" rule (Swater would mean Shallow Water).
This should help being a rule or making a Zora 2 enemy that walks on normal or shallow water (ala ALTTP).
I have been able to simulate this with marginal success. Make a clear combo that is of type pit. put it on the shallow water, or whatever else for that matter, on layer 1 or 2. Link won't warp because its not a combo on layer 0, and the enemies won't step on it because its a pit combo.
That's very clever, Ganonator. Very clever indeed.
-C