I would start by removing Q1,Q2,,Q3,R3,R4,R6,R7,R9 and R10 and re-wiring D3, D4 and D5 to ground, you save nine components and get exactly the same operation.
You will probably have trouble with biasing Q6 to Q9 because they all share the same bias source (R19). It will work if only one float switch operates but may not work if two or more operate simultaneously, you really need a bias resistor in each transistor base and you can increase the values of the resistors to ground to 100K or more quite safely to reduce current consumption.
Brian.