I wouldn't give up on them too easily. There is one clue in what you said that may help. Kendrick said "Col Hyatt and Capt Cally's" regiment. Hyatt did not assume command of the Crescent until very late in the war (after April '64). By that time two battalions had been consolidated into the Crescent and it was renamed the Consolidated Crescent. I have seen several service records that showed men enlisting after this date. This was probably due to fighting entering their home area and especially true for men that were too old or boys that were too young previously. Musters may not have been as carefully recorded that late in the war for some units. They also may not have officially enlisted but just joined in the fighting.
"Capt Cally's" would probably refer to Capt David Collie. However he was in Co. N, not G. He may have assumed some regimental duties due to the extreme loss of officers at the Battle of Mansfield. That's interesting that he would be listed along with Hyatt.
I suppose you have seen JS Kendrick in Co G? Do you know if there is a relation? There was also a Capt John Knight in the Crescent but he was wounded at Shiloh and dropped from the roll afterwards. I have an original morning report book for Co G of the Cons Crescent; I'll look for any sign of them and let you know.