Hi Ariel:
Need better pics to give any sort of opinion. I think the third one you show is actually from a pole arm. There are Vietnamese and Thai pole weapons of similar form.
Note a similar example from Vietnam here:
http://www.sevenstarstrading.com/art...page=vietsword Perhaps something in common with the
mak used by the Montagnard of Vietnam, Laos, and possibly Cambodia. There are also Chinese pole arms of similar form that may be the inspiration for the form in SE Asia. Philip and Scott could no doubt contribute more on the Chinese connection.
Ian.