Why 12v in venues? The only reason to use DC power is when you can't get AC, like in a forest or on a bicycle.

If you are going DC, look to use class D amplifiers - better quality car amplifiers, as you're a newbie. They use far less battery power than an inverter + AC amplifier. Also, don't believe the power ratings on car amps, they're usually peak into one ohm, on a good day.

As you've already started, what 12"s do you have?

The Pioneer is a decent enough class D (Alpine, & Kenwood are other brands to consider, avoid mostly anything else), but it's a 4 way amp, bridgeable to a stereo pair. You might want to look at mono car amps for bass duty, and run both speakers off the one channel in parallel: Class D car amps can drive 2 or 1 ohm loads better than AC amps, so two 12" will be fine. Assuming the 12" are about 250w &8ohm each, a 500 or 600w (into 4ohm) amplifier (probably marketed at four times that) will do you well.

Don't worry if you've already got a 4 channel amp, that'll work too, and cover whatever top cabinets you end up with. The good thing about (modern) car amplifiers is the in-built crossovers save you having to get a separate unit, and the bass amps have rudimentary parametric EQ.

I'm unsure if scoops are the best box for those drivers, but that's a whole different discussion, and one best had with someone more knowledgeable than I.