You shouldn't have trouble due to crayfish damaging new plants since your crayfish population is still low density. Look into locating some small variety or dwarf water lilies for a spring planting. Good Shoreline plants are water iris (blue), pickeral weed, arrow head, lizard tail, variegated sweet flag. IMO get them started in submerged containers first then when established and growing well with lots of roots transplant to desired areas.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=440475#Post440475 
