Also, I'm not sure what's going on with some of the leaves. Some of the leaves lower on the branches have blackened tips (only two or three have this problem), and others have slight curling, deformation and yellowing. The newer growth higher up (as can be seen in first picture) seems more vigorous and normal-looking. Is this mostly past/localized nutrient deficiency?

clip ,fruit yes. Leave, just remove those that look bad and destroy them in a way to prevent contamination. Keep a watch on the tree. Wait and see what other have to say

{{gwi:576595}}
Seed grown meiwa kumquat tree a 9.5 months age
click pick to open photobucket
thanks for showing your tree pic. I love looking at plant pictures