So far, as of this writing, there appear to be 18 recorded clears. The Healer representation is as follows:
WHM: 13
SCH: 9
AST: 5
SGE: 9
The pairings are:
WHM/WHM: 0
WHM/SCH: 5
WHM/AST: 0
WHM/SGE: 8
SCH/SCH: 0
SCH/AST: 4
SCH/SGE: 0
AST/AST: 0
AST/SGE: 1
SGE/SGE: 0
The most cleared combination so far is WHM/SGE with 8, WHM/SCH with 5, SCH/AST wth 4, and AST/SGE with 1. No doubles have resulted in clears, nor have any Pure/Pure or Barrier/Barrier (if anyone's even trying them)
The most popular overall healer is WHM at 13, then SCH and SGE tied at 9. AST is the least popular, but not terribly so, with 5.
All of WHM/SCH, WHM/SGE, AST/SCH, and AST/SGE (all four of the possible Pure/Barrier combinations) have resulted in at least one clear. So all "standard comp" (1 Pure + 1 Barrier) Healer team seem to be viable.
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EDIT: Statistically, at least, it seems a pretty fair distribution and every standard comp being viable, so that's a good sign, I'd think...even given all the weirdness with the clear race thus far, one would expect that to shake out in the numbers anyway (that is, whether everyone's cheating or some are and others aren't shouldn't affect this representation), so...I dunno, seems like a good thing. A bit better than the Tank situation where DRK is 100% of them. XD