you will get money during the second period and be able to fill those spots.
i'm not sure if you are actually on your first season? if so, good luck! fb/fcp is an interesting approach. you really want to make sure you have 12 players evenly spread out (or slightly heavier towards the guard side). stamina is a core rating for all players - every position you want to focus on a set of core ratings and consider the rest nice to have or something. anyway if you can get good balanced depth and stamina, fb/fcp can make up for a lot of imperfections.
i don't really break down core ratings by position as much by scoring/non scoring. you can have a mix of both groups (scoring/non scoring) - don't hesitate to have several / a handful of players down in that 0-2 distro range doing minimal work. your top 5 guys or so should be doing most the heavy lifting, and you can definitely have a guy like melin who is decently ahead of the rest of the team up around 20ppg. also in d3, you don't get true SFs as much as you get guards who can play SF or bigs who can play SF. as fb/fcp you really can just pretend SF is your 3rd guard position, that is roughly how most people play it anyway. some reb is nice, but you can definitely roll a 1 reb SF.
quick core list for reference - for your d3 fb/fcp (not in order)
non-scoring guard (pg) - ath, spd, def, bh, pass, sta (emphasis on pass)
scoring guard (sg) - ath, spd, def, per, bh, pass, sta (emphasis on per especially, but also need spd/bh. lp can be nice but nothing beats elite 3pt scoring)
non scoring big (most of them) - reb, ath, def, sta
scoring big - ath, reb, def, lp, sta (per, ft, and spd can be nice to supplement your big's lp/ath driven scoring - however - you can also live without them)
as you might guess, its often not that hard to get bigs who are can check the core rating boxes. guards, its harder as there is more, you have to be willing to sacrifice somewhere to get more somewhere else (sacrificing ath/def/pass on your sg to ensure elite per/spd/bh is the standard case).
getting started, i'd roughly optimize for cores and just ignore everything else. keep it simple. when you have a top 10 program you may want to start concerning yourself with more ratings, but you may not either. fb/fcp schemes tend to be the extreme version of 'focus on cores ignore everything else', so that approach should suit you nicely for now at least.