the only issue i see here is one of order
optimally, the amendments should be composted in the compost pile then fed to the worms {aka; nutrient cycling}
however; as described your amendments would be in more controlled proportions and humic action on the amendments sitting in the EWC should not be forgotten
the reason I am doing it like this is so I can dose the nutrients.. other wise you dont know whats what....
my worms get fed all the reject shit from botanicals and sprout teas so they are going to have quite a bit of nutrition anyway, but atleast I can then add actual measured amounts this way and they will be well broken down