Good to hear you have the Dayton DSP. That is exactly what you need. That being the case, you don't really need the PreSonus Eris E8 XTs, but they are very good. I have tried a bunch of monitors, and they are very good ones. The front porting isn't really an issue, since ports don't need that much room to work, a couple inches will do. You will need to give your speakers some rear space anyway, just to make room for the cables (unless you get cables with 90-degree terminations), and that should be enough space for the ports to work.
I have been toying around with Peace EQ a bit myself lately. I don't know how it could help you unless you can assign its EQ curves to specific channels. I know it can do that in standard surround sound setups, but can it do that with a pro-audio interface? Those tend to one have two-channel output. What kind of audio interface are you using?
One thing, I had to look up the Subpac, and if I were you, I would take it out of music production. It looks like fun, but the problem is how do you level match something like that with the rest of your sound? There is no way to do that since it doesn't actually produce sound. Again, you may be facing the dilemma of how much bass is really in your mix? I could see something like a Subpac making it seem like there is more bass than there really is, which is bad for content creation, especially in bass-heavy music. On that subject, when you get the sub, do you have a way to level match it with the speakers? It will be important to get that right. If its level is too high with respect to the speakers, the mix will be light on bass, but if its level is too low, you will have more bass than what you intend.