This is a shame in this year's FIFA, because 'true' CDMs have always been some of my favorite players such as Busquets, Matic, Toulalan, Khedira, etc., but their defensive traits (interceptions, height, aggression, strength) are purely only useful when they're standing in front of your Fifa 16 Account breaking down play. When any true CDM player like Khedira pushes forward because of broken game mechanics, he gets 0 use of his defensive and physical attributes if he's hanging around your opponents box since they tend to lack in the pace, shooting, passing, and dribbling department.
With that being said, I've had huge success with playing more "box-to-box" midfielders in all midfield positions in the false 9 (it's one of my favorite formations too) and setting their formations on free roam so that they can interchange with each other, all attack and defend equally, and never be caught out of position. This way, you don't rely on specific midfielders to do specific things, and will add significantly less predictability to your play. For the CDM, I would say to have them the most defensive/tall of the 3 CMs that you choose. Players like Parolo, Vidal, Yaya, Pogba, Strootman, Nainggolan, Fellaini, or Lars Bender are good here (good all around stats and all close to or taller than 6'). Hope this helps!
433-5: This one is definitely my favorite, but I think it's a bit harder to build a team that works with it simply because every position between the midfielders and forwards are equally as important.
Make your CDM the tallest and most defensive of the 3 box to box CMs that you choose.
Your wingers must be efficient finishers. This part is crucial, especially since the wingers tend to act as strikers here and because they receive the most passing support from all 3 midfielders + your CF. LW examples include Nolito, Pedro, Reus, Perisic, Neymar, Alexis, Son, and Hazard. RW examples include Robben, Hulk, Bale, Berardi, Promes, Volland, Walcott, and Vela.
Your CF is a bit tricky. You can get a little creative here, and I would also like to go ahead and bust the stereotype that you CF must be an excellent passer to succeed here. This is not true. If you have a CF that can't pass, then don't pass with them. Problem solved. If you chose to go this route, then I would opt for a tall/physical striker than can hold up the play to make up for the fact that he can't distribute (Morata, Mandzukic, Jackson Martinez, Higuain, Benteke, Negredo, Bacca).
However, I don't think anybody can deny that having a CF with decent passing ability is definitely a plus (Muller, Rooney, Griezmann, Benzema, Tevez, Ibra, RVP, Di Natale, Raffael, Max Kruse). One last thing that I will add about the CF is that I would avoid using natural CAMs in this spot (you can, but the options are limited [James, De Bruyne, Hamsik, IF Perisic, maybe a couple others out there] since CAMs tend to be small and weak) and that 4* skills is, for more fut 16 coins, almost a MUST HAVE. If they don't have 4* skills, they better be pretty god damn good at something else to make up for it.