Good to hear from you. Rare Moro blade forms are always going to be hard to pin down as to their origins I guess.
Of the examples you posted, I think only the top one is of a truly similar style, with the clear "cut out" segment and the parallel edges of the blade near the hilt. Interesting that it is found on a Visayan knife. In fact, that particular blade looks very similar to a Sulawesi badek pictured in van Zonneveld (p. 27, no. 24) but that one has a Bugis hilt that is obviously different from your example.
Perhaps this "cut out" blade style arose elsewhere (Java, Sulawesi, the Lesser Sundas) but was incorporated into the Moro and Visayan armamentaria as a rare form. You might like to check whether
larbango (Java) is a term used for a Moro weapon -- just as
bangkung (Bugis),
jimpul (Kenyah, Sea Dyak) have been borrowed from other ethnic groups to describe weapons used by the Moro.
One last question and I'll let this one rest. Since you have handled this particular item, is the hardened edge inserted (in the usual Moro way) or differentially heat treated?
A picture of the etched blade and edge would be nice to see.
Ian.