I did read it but decided not to post, as i still feel the same as before, i think you should do one change at the time and see how it reacts, like for 3 people posting here (including me) concur that the first step should be reseating the CPU heatsink, but in my experience haswell quads with hyperthreading run very hot so might not help that much, still should help some.
Now on the fans, more air will lower temps no doubt, but the question is weather the extra noise you will introduce with more fans will justify what drops in temps. You should first try to run all you fans that you have atm (2 fractal and 1 antec) at full 12V, no fan controller no software to reduce their speed, and test it see if the CPU temps lower some, and see how the noise increased, and if you are willing to take more or not. All of this is free, its just a matter of time and testing.
Now to answer you last two posts, out of what you want to do,
The NF-A15 are not standard frame, thus they might not fit in slots like frontal of the case, where NF-A14 should fit, weather its PWM or FLX depends on how you want to control them and with what, for example to use the fan controller on the case or CHA_FAN headers (1,2,3) i would use FLX and for using them via PWM FAN SPLITTER (like swiftech
then i would chose all PWM.
One the cooler, NF-A15 PWM are ideal in terms they are the same as TY147 that came with your cooler, mostly physically, the frame of the fan is almost clone, so the included clips will work fine, but at the same time the cooler only comes with a set of clips to mount one fan, you seem to want to do pull push with two fans, here you wont have a second set of mounting clips so idk they will mount it, that aside, the space on the back of the HR02 will be very close to the case to the point that im not sure if a second fan would fit or how much it would help, this are all things that you have to prepare before spending the money on extra fans.
Now your setup is very similar than mine, the cpu are identical since im not overclocking, and CPU cooler is the same in my own testing, so in essence if you go with 4x Noctua NF-A14 PWM (3 in and 1 out) you can expect similar temps than me, given the same ambient temp and correct seating of the cpu socket, that said i still hit 80C on prime95, on fans at 650rpms, if i allow the 4x NF-A14 PWM (case fans) to reach 900rpms i drop like 5C in temps all acoss the cores, so asume around 75C, but this increases the noise significantly to me (might not to you), and if you allow them to go into 1200+ i bet you will get temps close to 70s, but here they really become loud (again to me), but im very picky about fans, i have never own a fan that above 1000rpms is quiet, i try to have as much control as possible to lower them to points where i cant hear them, even at the expense of hotter running componets, all this decisions have to come from you and no one can tell you whats better, you are the one that has to live with your PC and with the noise it will produce.
We all have different settings, specially ambient noise, what might be fine by me might not by you, all is relative to each user, and for this is why tweaking your PC to your personal preference is important. If after you test the fans (the one that you have already) you feel you still need more cooling then go NF-A14 for case fans and NF-A15 PWM for cpu fans, how many... again depends on each setup, there is no magic number, there are points where its worth it and some that its not, specially when you add too much the cooling starts to go into exponential curve where you add tons of air but there is little gain in temps.