Any advice on how to use the Merchant and Time Mage¿ They seem kinda... useless.
Pay to Play by Merchant increases crit rate by a lot. Using it three times on a character increases their crit rate to 1000%, which is the max. Unless you're using an axe, this pretty much guarantees a critical hit when that person uses an attack, which is equivalent to double of the usual damage. Hedge Risk halves damage on the user, which may be useful in a pinch. If you use the Healing Lore support ability from Salve Maker, I believe it improves the amount of HP/MP restored when you buy an item using the Pharmacy skill. Also, if money farming is your thing, there are AFK pg farming techniques that utilise Merchant's Big Pharma to constantly heal and extract payment from the enemy.
As for Time Mage, Regen and Reraise are your most useful skills. Reraise is always helpful, while Regen recovers 3% of HP per turn, so it's more useful for boss fights that drag on without the bosses dealing constant damage towards your party (Kamiizumi, Kikyo, Victoria, Braev are a few examples). Regen also overwrites Poison and vice versa, if you didn't know. It would be wise to invest in the Black Mage's Group-Cast All support ability so you can have these buffs on your characters using only one cast each. Haste and Slow are also useful for moments when it's important for your characters to act first during the next turn.
I just finished this game a few days ago and I think it's pretty good. Don't think I've ever experienced a final boss segment as amazing as this game's. I also found it amusing that I beat the game the same way I did FFV, which was by spamming Mimic. Got Agnes to use Pirate's Torrent or Amped Strike to hit for 9999 damage, then had everyone else except Ringabel Brave and Mimic her. Ringabel's defense and healing were both really high, and he was equipped with a Ribbon, so the strategy was relatively safe lol
It was a pleasant surprise for me to find out that the lead writer was responsible for Steins;Gate and the composer was the same guy who did Shingeki no Kyojin's opening theme. I'm quite happy that both of them are working on Bravely Second.
My 3DS code is 5129-2351-0368.