Sorry - RKT is rice krispie treats. You can buy store-made ones and form them in a shrimp-shape, and cover with fondant ! Piping gel in the right color combination - maybe a mix of red/orange/yellow so it isn't a flat color would be nice - definitely try it on a test piece first!!
As for how to use coconut - this is how I color it - take a bag of shredded coconut and put in a ziplock plastic bag with a few drops of green food coloring (not the wilton gels - the more liquidy kind you use for coloring easter eggs). seal the bag and then shake it up and the green coloring will disperse throughout the coconut. then add a little yellow coloring in and do the same. some of the coconut will be green, some yellow and some even a little white which is fine because lettuce is not a flat color. I will try to post a specific pic of mine with lettuce in a sandwich separately - I've been having trouble looking at all my photos - it keeps crashing my computer - so I want to send this info separately!
I'd be worried about a glass on top of cake too - try getting a plastic glass at a party supply store. and maybe a cardboard round between the bottom of the glass and the cake !
it's not too many q - happy to help you!