Remotely monitor condition of fuse
The simplest solution I can think off would be to use a 5V isolated DC-DC converter.





R1 &amp; the LED are the basic indicator. When the fuse blows the LED lights up. The LED current is ~1.7mA. 

D2 and R3 are there to protect the DC-DC output if the fuse is blown and the output of the whole battery section for some reason goes to 0 volts. R3 also protects the LED if the fuse is blown, BAT1 is removed and the BAT1 wires are then shorted. 

You need only a very small DC-DC converter. The smallest are less then two dollars. You must use an isolated type. You need one circuit per fuse.

The DC-Dc converter input can come from the common battery 12V section.
You will not get an indication if all fuses are blown! The alternative is to power the DC-Dc converters from an independent source.