The h115i will restrict the airflow; so you might consider each of those fans as moving 1/2 as much air compared to an intake or exhaust without restriction.
To provide the best balance I'd have 2 x intake and the 1 x exhaust as you propose, but also have the h115i fans exhausting air. This is a very common model; as it also uses natural convection to take the hot air out of the case (hot air rises).
As an aside - balanced airflow was shown to provide the least dust in a (fairly unscientific) LTT video on the topic, and slightly negative airflow is commonly believed (rightly or wrongly) to give better temps due to a reduction in vortexes. I'm not claiming either of those is valid, but in the absence of any real data on your specific situation might be worth an experiment.
Do let us know what you decide!
I'd agree with most here except the hot air rises thing. In a pc case this small the air will go wherever its pushed.
So yeah op you go more positive you get more dust. You want it neutral as poss imo. Best cooling. Least dust.
People will argue where you put your aio but id say at the top as exhaust. I know your cpu won't be getting fresh air there, however;
A) your cpu won't be firing hot air directly at your gpu (and let's be honest this is where temps really matter for fps - ergo gpu boost)
B) your case won't be getting filled with nearly as much hot air to get rid of, benefiting other components
C) it allows you a close ratio of cfm in/out:
2 x 14cm in
2 x 14cm out (restricted so count as say 1)
then 1 x 12cm exhaust at the back.
Thats easier than trying to mix/match the fans on top for in/out
