Recently fed fish some frozen food (A mix of brine shrimp, rotifiers and some other stuff, its what they were on at LFS) and both Cardinals and 1 shrimp were interested and ate a good amount of food. I couldn't tell for the other shrimp as it was in a cave and could've easily gotten food through a nook or cranny in it. In freshwater the common theme is "if its eating food, its probably alright", which has helped anxiety in that regard.
Should be fine on overfeeding considering the amount left over, will continue to update for awhile.
Updated charts and image of tank below, only live-rock for filtration. Don't mind the background mess, unpacking from recent house move been slow.