Hi - Interesting topic, this is a little aside, but I thought I'd offer my two cents about the term "Kali" as I think it has been developing some false associations. These are just my own opinions/observations and I know these discussions can be contentious, so please understand that I don't mean any disrespect to anyone. (I'm open to being corrected.
The term Kali is not a tell-all as regards to where a style is from: i.e. Pekiti-Tirsia Kali. I've never heard anyone associated with PTK say that the style originates from the southern Philippines or is a Moro art. Personally I see the adoption of the term "Kali" for more cultural reasons: would you really want your nation's traditional martial arts referenced in the language of a colonial power? If I remember correctly Tuhon Leo Gaje first made this point during one of his pre-seminar talks.
In trying to recollect a discussion somewhere else in the binary stream, I believe it was said that Dan Inosanto was the first person who used the term in print in his book on FMA and then it took off in common usage from there. The term may be a fairly modern one.
I live in the US, and here, the only style that I have ever seen that I would consider to have influence from Silat is Villabrille Largusa Kali, and mainly because they use "cross-over" footwork similar to Sempok/Dembok in Silat (one foot steps in front or back of the other - from my experience a big no-no in other FMA - never cross your feet). Talking with an instructor of mine regarding that style, it appears that they do orient some of their movements towards dealing with heavier weapons which could be an indicator of Keris, etc (my inference - not my teacher's). But then again, the history page posted on the Villabrille Largusa site talks about Villabrille fighting a Moro Prince
who practices Silat/Kuntao....
So if you are searching for info on Moro arts I would caution you in relying on the term "Kali" alone.
I hope someone has some good info for you though - I often been curious about the same subject. I think you are on the right track though with the connection between movement and light vs heavy weapon: very different games. Another avenue of research may be Borneo....