Well, I really hate to post this as it's so fun to use right now, but...
When leveling up the character, you can exploit the reset feature to gain FP for free (and possibly all other perks from the different trees? haven't tested.)
To duplicate this, you:
1) Select leadership tree and the 5 FP skill
2) Reset your choices
3) Select any other tree and whatever skills you want.
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You now have a higher FP cap even though you do not have the leadership or skill points.
This also works going from any level of leadership not just 0 ->1 -> 0