african cichlids with crayfish crabs or macro?

hi folks,

currently i have a 4ft tank keeping 15 cichlids

stock list as below:
3 yellow labs
3 P.acei
1 rusty
1 electric blue hap
3 P.nyererri
1 sydonitis catfish
2 blood parrot

is it possible to add 1 crayfish or FW crab or Macro shrimp?

i am looking at the inverterbrates below

zebra/tiger crayfish
http://www.shrimpnow.com/content.php...bra-Lobster%29

fuzzy claw marco shrimp
http://www.petshrimp.com/fuzzyclawmacro.php

panther crab
http://www.panzerwelten.de/forum/thread-1748.html

thanks

also looking at this shrimp

African Fan Shrimp
http://www.shrimpnow.com/content.php...pire-Shrimp%29