So, if they built a team where it is Kyrie-Seth-Harris-KD-Simmons five out there, which would be very difficult because it lacks center but they can just rest one of them and put a center in there and just change whoever is resting, that way they will always have 1 center, 1 amazing passer Simmons, and 3 shooters at all times. That's a team that can fight for a title with the right coach if you ask me.
Kyrie Irving and Seth Curry shouldn't be on the same floor most of the time. Seth is more suited up for being a backup Point Guard for Irving. Ben Simmons though can handle the PG position like in his Philadelphia 76ers tenure but looking at Brooklyn's roster, I see that he is more suited up as a Shooting Guard and a backcourt duo for Kyrie Irving. 
There's no question about the performance of Kevin Durant, Kyrie Irving, and Ben Simmons. They are all good and explosive. However, since these 3 are known 
"divas" in their own way, I hope Coach Steve Nash will be able to handle these 3 properly wherein we can see the cooperation of these said players to their coach. Especially Durant, there's surely an awkward relationship now between him and his coach. 
Anyhow, I know they are professional and will do their best for the team.