With leaks going around for Nu BW being in Hawkeye, I can definitely see a scenario to where we see Florence in an end-credits, perhaps with Bucky.
Power Broker is on two beliefs for me as of now: The first being the obvious, Power Broker is The Mandarin. I don't think there needs to be as much of an explanation to why I'd think that, because
@Nick summed it up nicely. That said, if Daredevil and Jessica Jones are being rebooted in the sense to be integrated into the MCU better..i mean, one person comes to mind for me. And I would actually say a case, for David Tennant to pop back up as Purple Man, using the Power Broker alias as a cover.
Purple Man would be an interesting villain to bring back up, more so as an overarching villain for the sake of the MCU's TV shows, especially if they borrow small elements here and there from the JJ Netflix series. I would understand why if they can't, due to the timing of the relapse back, but I kind of hope they find a way to bring Tennant (And D'nofrio) back as their villains for when they're tackled again.