Hero's Bracelet is better than the Allagan Bracelet. Onion Shield vs Holy Shield Zenith vs Allagan Shield is all debatable and dependent on what content you're doing.

Since you just hit 50 and 2.2 is literally a little over a week away my recommendation would be: get to full i90 with 481-483 accuracy. Your goal shouldn't be BiS, just get to that point and you're solid. If you happen to get something that doesn't drop you below 481-483 accuracy and increases your Parry, equip it. The reason min/maxing is pointless (and, really, was pointless in all of 2.0 and 2.1) is, like shoki said, because 2.2 will come and everything will change. Having x amount more Parry will honestly not make or break Twintania, so try your hardest not to stress over what's best where.