One assumes the restrooms are not noisy, but if you're in row 13 you may hear the whole suction business. Additionally, if you're superstitious (and I'm not) row 13 may not be preferred.

Row 12 A & K are looking pretty good, IMHO.

As for being "protected" should they sub a 744, your seat allocation will not mean anything. They don't directly "translate" seat allocations from one type to another, so your 744 seat would be based on profile preferences and status