OK my 2 cents worth.

NEVER allow external loads to be energized without control. i.e. if the control is by CPU then the CPU should issue an output enable only after proper I/O conditions have been established. As I understand your circuit it is assumed that all relays will be off until the CPU assumes control so a power on reset may be fine. I like to disable external power sources until after the CPU has finished it's powerup checks and set the proper output conditions then enabled the outputs...

I like belts and suspenders.

ALWAYS use transient suppression (a 1N004 or better) DIRECTLY across any switched inductive load if possible. You can get some really large current spikes from some really small inductors and some big power from larger ones. Transient suppression is usually less trivial than it seems.

Never use JUST a cap for transient suppression on inductive loads...it just makes things worse usually(inductor + cap = tuned tank = long oscillation period if no damping resistor).

Always provide transient suppression for the switched load also (R/C,Diodes for DC, Transorb,R/C,Varistor for AC). These should be as close to the load as possible, if not directly on the load then as close as possible to where the load leads attach to the PCB.

ALWAYS ASSUME THE WORST...You'll seldom be wrong!

Yadda yadda blah blah.........Good luck.

Art