In this case, all the non-stamina trinkets from MoP are utter garbage due to being under budget. Unfortunately, most of the stamina trinkets scale bad down to 468, which leaves you with three choices, all of which give you +1270 to stamina plus active or proc (described stats are the ones you'll received inside the dungeons):
1)
Iron Protector Talisman - 15% chance on hit to grant 3386 dodge (3,82%) for 15 sec; 55 sec icd.
2)
Relic of Niuzao - On uses 7860 (8,88%) dodge for 10 sec (1 Min Cooldown).
3)
Rook's Unlucky Talisman - On use 14% AoE reduction for 15 sec. (1 Min, 30 Sec Cooldown).
Relic is the absolute best trinket for CM, with the other two being situational depending on the pull and boss encounters. Iron Protector would be the default pick while Rook's is ideal for AoE mobs and bosses (specially Siege of Niuzao Temple).
Regarding specific gear pieces, if you are going for the realm title, min/maxing is absolutely needed. You didn't specify which class are you using so I can't give you any advice beyond recommending you to actually go to wowhead, and make several lists, each with every available piece, from 463 to last tier (or the tier you have access to) and comparing which piece ends up having better budget. Remember that the piece with most sockets takes the crown. Finally, since 5.4, gemming has taking a bit of a turn for Warriors and DKs and now is practically BiS to gem for dodge and parry, since they will each grant a 75% stat bonus to crit.