Would This Restock Plan Work?

[BaylorPerez]

to a point yes, Cories are interesting and very active. though some say they are mostly active during the night ( lights off ), but i find that to be on their cories. as mine are really active during the day when i am home, then are dormant when the lights are off, my New amano on the other hand are night crawlers as they are active during the night.
 
But cories love to explore every nook and cranny, even examining the same sand pile for hours at a time. so as long as the sand is over the rough substrate by 1-2 inches you should be fine 

 

[cooledwhip]

just posted a thread about my substrate. can you guys please take a look at it

 

[Ninjouzata]

The sand would likely sink through to the bottom eventually.
 
As for the crabs, lobsters (I assume this is more referring to crayfish), some have success but I would not recommend it as they could harm the fish.