No. Don't reforge crit/haste to hit. Our stats goes like:
1. Agility
2. Hit, if not hitcapped.
3. Crit
4. Haste
5. Mastery
Therefore you should reforge your mastery into hit instead. And all the mastery you have over, you should make into crit. If the item already have crit, go for haste with it.
About the trinkets I think you should go for the key. Seeing it proccs 1710 agility, which is 1/3 of a heroic geared hunters agility at the moment. And seeing agility is our primary stat, it's a huge boost. And you need the hit anyways. And make all mastery into crit.