Ok if you just repotted then they should perk up soon...

I think you have the full FF trio, which should take you through flowering. I don't know anything about FF, maybe someone else can chime in if they use something else to supplement what you have.

I think the 4 week thing for the soil is just an average, they might need it sooner, or maybe later, so tough to say. Start with low doses and work your way up. If the leaf tips start to yellow and get crispy, just use only water (maybe a flush if it gets bad) and back down on the nutes.