So, here's an update:
I ended up purchasing the
Metra Dash kit from Crutchfield for a couple reasons. I was getting a lot of misinformation from the other types of dash conversion kits. For one, it was difficult to find where to buy it from, though it did turn up on Amazon (Canada for me). Though, trying to figure out if the deck had Android Auto was nearly impossible. You could get it (supposedly) as an add-on from various sites, and even as a separate purchase from Amazon. But they ended up emailing me and saying it was no longer possible with the Android 9.0 units. It was all too much of a headache, not to mention that those units were $700-$800.
The results first: I got the unit all installed successfully. It works great, all the buttons and HVAC and everything, even the steering wheel control controls. The instruction were a tad confusing at times but I got it to work in the end. I am satisfied enough with the look and also with having the HVAC controls ported to a touch screen in a new location. This bothered me a lot when looking at which options to go with, not now, it's no issue at all. I'd insert a pic but I don't wanna deal with any pic upload link bizness.
Speaker upgrade:
I DIYed the **** out of this part. First off, plan to struggle mightily with door panel removal. For me, it was very difficult and you definitely need to purchase a special door and trim removal kit. Still, I managed to break about 7 of the little clips that hold on door panels. Make sure to watch the youtube videos on how to do that.
I put new 6x9s in the front. Instead of buying the brackets and wire harnesses you need (which Crutchfield makes quite easy to purchase) I ended up modifying the existing speaker/bracket combos. I just cut em up and then glued new speakers to the bracket. then I soldered wires together. Seems to work.
However, I recommend NOT messing with the front door tweeters. I tried to change those out and for some reason, the new ones sounded terrible and I think messed up the ratio of the signal or whatever.
Back speakers I put in a couple of round 6.5"ers with the same method, however, I feel like I should have put in 6x9s. There's enough space for sure, but for that you would definitely need to purchase the proper brackets.
Sub woofer:
I built a DIY (crappy) sub box that fits just so in the cavity behind the rear seats. With precision measurements (lol) you can JUST get a 12" sub in there. However, I suspect my sealed box is far smaller than recommended. Still, seems to work well enough for my purposes.
Note that the best way to get amp power cables are through a grommet right under the driver side area, below your left foot. I saw a video on Youtube and it was bang on. If you thought going through the glove box was the route, i definitely recommend finding the video that shows you how to go through the driver side floor grommet!
That's about it! My deck works, speakers and sub work, though, I do now have a dash warning for "check battery system" when I have the sub on with accessory mode only. Don't know if that's due to a mistake on my part, or a natural result of drawing lots of power when the car isn't running.
Note: My vehicle is a base model 2012 Explorer with the 6 speaker system.