i always picture Crayak as a massive gorilla cyclops stuck hardwired into a chair with a single bloodshot eye looking down at them.
as for the Kelbrids, in my early fics (before i got lazy), i kinda pictured their culture off of early native american tribes. they war with each other but they are trustworthy to a fault.
as for mental image of the Kelbirds, i came up with two castes in my mind, the workers/warriors (think of a huge 10 foot spider covered with armor and space age tech) and the leaders/scholors (think of a spider centuar with eyes with the texture of glass).