Hello Michael, to my opinion the symbols depict
a Spanish fortress (enemy),
a kampilan as symbol for battle and
a dog, which is also a symbol for alertness (aside from being a pet).
The naga/wormlike symbol is actually a centipede which are feared for their painfull sting (feels like being stung with a blade)! This centipede symbol is actually also used in the north sometimes engraved on Headaxe blades.
Best, Wouter