The PRV DSP is a 2-input, 8-output digital signal processor EQ and electronic crossover; it's not complicated, at least that unit is not complicated, but it serves a specific purpose, and using it any other way than fully active is an effort in futility.
Using it the way you're asking is not going to benefit the system and will actually make things worse. Time alignment won't help your system if configured the way you are considering, as the staging and other factors will be much more adversely affected.
All is not lost, though.
Here is the best way to use the equipment you already have if you're not ready to go fully active, and fully active with adequate power.
You use the Focal components on the right and left sides of the cabin, i.e., left and right doors, and the dash; however, that looks for your vehicle - with the passive crossovers, this takes the worry out of blowing anything up.\
You take the amp and run it in 2-ch mode for 160x2 like this.
View attachment 70438
Settings for the amp like this:
View attachment 70439
Now you have 160 watts a side to the component speakers and the crossover does the frequency dividing, which takes care of protecting the tweeter from low frequencies.
If you are not using a head unit and plan to use the PRV as your line out converter, again, don't bother until you are set up to go fully active, which would involve using the Alpine in bridged mode to just the 6.5' woofers and a 50-75 watt x 2 amp for the tweeters.
In the meantime, you can simply get one of these, tap into the existing front left and right speaker leads coming off your head unit.
It can be used later to feed the PRV or any other DSP you decide to get.
The unique thing about the kicker LOC is that it's remarkably clean and will handle 55 watts of high-level speaker lead inputs from your OEM HU.
Another neat thing about it is that it will use the voltage from the speaker leads to create a remote turn-on lead for your amps, which eliminates the need to find one or create one from the cars ACC triggered power-on somewhere in the fuse box.
Here is where it gets a bit confusing.
You will run a y from both of the kicker LOC outputs to split them into dual right and left outputs. You will then take one R and one L, run those to the Alpine, use another set of "Y" splitters at the amp to get dual R and Dual L to the amp as I demonstrated earlier.
You will run another R/L RCA cable from the remaining L/R outputs off the LOC to the subwoofer amp and use the crossovers on the amp to set up your subwoofer, probably somewhere between 70-100 hz, wherever it blends best with the focal sets up front.
Here is a rough draft of how that looks.
View attachment 70441
View attachment 70442
This is the best way to setup the system with the existing equeipment.