Hi there. Most of your FF-related needs can be found in this old thread: [Class] Featherfoot Thread
A good amount of FF skills are high-damage, single-target, melee attacks and the class is this game’s “Blood Mage” Exploiting bleeding and cursing on the enemy to maximize dmg or heal health. It’s a great soloing class.
Linker goes really well with FF on account of not just allowing your melee strikes to hit multiple enemies with JP and HK, but the JP attribute boosts FF skill dmg(Poison).
FF1 is usually used in builds for the self-healing and not much else.
FF2 grants you one of the hardest hitting magic attacks in the game, Kundela Slash, and there is also Blood Curse, which allows Wizards to heal the party with an aoe lifesteal debuff, but it is a risky attack to use.
FF3 has a semi-unique skill called Enervate that applies a ground-aoe debuff that multiplies dmg to those affected. It’s similar to JP in this sense.
Do some research on the build you are aiming for. If you want solo potential I do recommend a L2, Thaum 2, FF3 build but other solo-friendly builds are available. The recent patch has resulted Thaum being nerfed quite hard and unless you want Swell Body, you can factor Ele for some aoe.