I appreciate your help very much.
Glad to hear!
TIL that BitMinter also does child pays for parent, and it seems like they look at all possible branches...
I was under the impression that:
1. b12a71...(0 conf 0 fees)
/ \
Unspent A 2. 862711...(0 conf 0 fees)
/ \
Unspent B Unspent C
but apparently you spent A with a little over 0.0003 BTC fee, and BitMinter placed 1, A's spending tx with fee, AND 2 all in the same block.
A very interesting discovery. I'll have to make note of that.
Glad they confirmed for you!