Hi Carve. I started writing on an answer two times, but had to think a bit. So, here goes a third try...
The "problem" with a three board quiver is that you will expect each board to be a _perfect_ fit - why else have as much as three boards. And since the range of a modern board is huge is should be easy, right? Well, in practice, regardless of how many boards you get, there will always be compromises in some area.
In your case, the freestyle board seems like an easy choice: Flare 98. I seriously doubt the bigger one would do anything better with 5.6 as the biggest sail. The smaller (88) might be if you do a lot of high wind freestyle in choppy waters too, but from what you write you don't. So Flare 98 it is.
For the smaller boards, there are EVOs and Kodes (and Evil Twins, but I don't think thos are the best option for you). Both E and K are all round and do most things well, but EVOs are more wave riding oriented. They for sure make riding waves in the exact conditions you describe easier, but you will loose some of that crisp B&J feel. So this is something you value you will be better off with Kodes. You will have to drive the board more through the turn (ie it requires more technique to rip in bad waves) but they are still by all means excellent wave boards - you just don't get as much "help" to get vertical and to keep speed. This goes for both the small and the big board.
So, if we assume I'm right and you are more after the Kode feel, then we just have to figure out the sizing. And here comes the tricky part. The Kode 74 would be excellent to have since it will be the most all round of tem al at your weight. But it might feel a tad hectic in the really windy stuff. It will be manageable in powered up 3.7 (at least it is for me and I'm 70kg) but not as relaxed as a smaller board. The plus side of the K74 is that it will work all the way up to 5.6 if it has too. So you can without worrying get the Kode 86 as the big board.
The Kode 86 with it's higher volume and more width and tail width will be nicer for high wind freestyle. It will plane a bit earlier and sail more relaxed with the 5.6 than the Kode 80. And it will be less demanding when it comes to keeping speed in slow waves in wave riding. It will on the other hand reach its limit in powered up wave riding and on a faster wave than the 80, but with the 74 in the quiver this will not be an issue.
If you instead go for the Kode 68 you will have than faultless high wind control boards you talk about. It will handle 5.0 well, but due to the shear lack of size, it will require more drive to ride waves well. If you like super loose boards or ride powered up, then it will be no worries, but there wil be times when it just feels a bit to small. Not so much because it will sink and plane late, rather because it will not keep the speed in the wave riding unless driven well by sail/wave/sailor.
So, the K68 coupled with the K86 will give you EXCELLENT range and top performance both with small and big sails, but leave to little overlap in the middle. Some people would for sure be happy with that, but my personal experience is that it pays off more to have lots of mid range overlap because this is where you spend most time and being able to choose between two boards for similar conditions is the BEST way to tune the on water feel.
So, with the K68 in the quiver, I would recommend the K80 as the big board. You'll loose a bit of effectiveness with underpowered 5.0 but some of it can be brought back with a bigger fin. And you'll gain performance on a wave as soon as you're either powered up or the wave is getting better/bigger/faster. With the K68+K80 you can choose a big board for when you want power and speed and bigger margins in the wave riding and vice versa with 4.5-5.0 (and even underpowered 4.0). And often when the wind changes, you'll be able to change board instead of re rigging to stay planing or to stay controlled. Very nice, if you ask me.
I personally had both the K86 and K80 this season, and when I went wave sailing I never even brought the 86 since the 80 in good enough also in light wind/slow waves/onshore for me. So I would for sure go the K68+80 route, particularly with the F98 in the quiver.
But if you do like som more board under your feet and want to effortlessly fly in marginal 5.6 too, the K74+86 will be excellent.
So as you see. Even with three boards there are compromises to be made. Regardless of the sizes you can choose from this will always be the case. But on the other hand, any combo will work really well. It's important to remember we are discussing nuances here. But again.....there are some things to think about.
Please tell me if you have more questions (like if you're in fact also interested in EVOs).