How different is a Monk / TBM different from a white Mage when properly espered?
Has three swiftnesses, Esunaga, Curaja, buffs, WAY more HP, decent physical damage, amazing Esper overlap... I can find virtually no information on this pairing online.
Edit: My self-imposed goal is to make a party of 3 that do not overlap jobs and who use all Espers between them.
The first thing is a lack of cure spells. You wouldn't be much of a healer until maybe halfway through.... And, even then basically no AOE cure for most of the story: basically Cure until Mt. Bur-Omisace once you can get Curaga and use it via Quickening 3, and then no Cura or Curaja until a late game esper.
Whether this is OK or not really depends on your character levels and weapons. If you're about the same level or slightly higher than monsters/bosses, and you're maybe stealing or looting a few good weapons early, it'll heal fine enough. You'll burn through encounters faster and Cure -> Hi Potions -> Curaga on a Decoy Tank (TBM does help with reducing your need for AOE cures) then you'll be OK.
But if you're a bit underleveled or 'normally' equipped, you could definitely feel the big lack of AOE Cura and also a much smaller MP pool without Mystic Armor.
Endgame though it's mostly stats, either Augments or especially Items. You're going to have access to much less MAG and MP without Mystic Armor.
You character matters a lot here. Ashe has 78 MAG at Lv99 and it decreases to the lowest two Balthier and Basch who have 63. Only 10 Magic Lore so either 88 to 73 MAG.
You'd definitely give the Magepower Shishak to this character so +5 there. You'd probably go with the Genji Armor too since your melee weapon could use the STR too and if even your healer is purely a Heavy Armor class, your other two characters may also be using the Grand Armor and Maximillion anyhow.
No staff or rod is OK because Holy doesn't effect cures. Your Whale Whisker would hit pretty hard, even sans Genji Glove you'd easily hit 99 STR. But your MAG would likely only reach 96 to 81. So on Ashe or Penelo, you'd basically heal the same as a WHM with worse MP. But you'd have difficulty making a MNK/TBM Basch heal as well as a pure WHM Basch.
You may have MP problems yet even endgame but when even your healer is smashing stuff with a Whale Whisker you're probably burning through fights pretty fast, so you can probably just cure/ether up between most encounters. Some of the biggest Hunts though you could run into MP/MAG problems if this character is Basch or Balthier I guess. Sort of depends how many elixirs you wanna burn haha. And on the flip side, it is you're likely to be doing/receiving a lot more damage than a traditional MP so MP-combat augments will help a lot. You may also get some synergy from Hashmal (assuming maybe for some reason you never really used a KNI and wanted to use Adramalech elsewhere), though I think it's a waste to use Hashmal to give a MNK Cura (who's already getting Curaja and Curaga) when it can give a KNI Curaja, Bravery, and Faith, and a MNK/TBM can just get Cura from Adramelech instead (but now you're missing Channelling 3). All of which, it's worth noting again, are mostly endgame,