In the main GlyphData.xml I think the location (sortName) field for “wavyhamzabelow-ar” should be ar2882; it’s currently 2880 which is already used by “gafsarkashcenter-ar” two letters up, and it’s sandwiched between 2881 and 2883.
I fixed the double sort name. I’m not sure about the sort names of “lam_alefWasla-ar”. Fixing them would change the sorting of the ligatures and cause unneeded changed to peoples files.
Ideally the final form would be just after its isolated form like the rest of the other lamalefs. Right now it jumps somewhat arbitrarily which is mainly noticeable if there are other ligatures that happen to fall in between that 0010 and 0100 location (otherwise it’s mostly with the rest).
Here’s what happens currently if, say, you add some tooth+yehbarri ligatures:
For what it’s worth, I’ve sorted the same data above in my GlyphsData.xml file like this, but moving just the lam_alefWasla-ar.fina ligature next to its isolated buddy would be nice for most people I’d think: