I was wondering if the big exposed kan of south wind be considered a concealed triplet as well
I'm afraid not. It was a concealed triplet when it was in my hand but when I called that 4th south wind, it became an exposed kong, which can be considered an exposed triplet.
The hand ended up as follows:
Pong of seat wind (north), round wind (south), and white dragons--- 3 han
3 concealed pongs (triplets) of west, north, and white dragons-------2 han (no south listed here)
Toi-Toi, 4 pungs and a pair, open or closed-----------------------------2 han
Honroto, all terminals and honors, open or closed----------------------2 han
Honitsu, half flush, one suit and honor tiles, open----------------------2 han
2 dora tiles, the one dots---------------------------------------------------2 han
Incidentally, if you don"t already know, the red dot in the middle of the white dragon is an optional rule called haku pocchi. It is a wild card only after riichi and with ippatsu, otherwise, just a regular white dragon. I only use one.