Alright guys, it looks like I might be out of my depth here. Just spent about 2 hours and did not solve the issue.
So to put it quickly, I wasn't able to "find" the optos from the bottom. I tracked where I thought the general area they should be but honestly they're all tied up there with the van and everything going on in that area. I unscrewed a couple screws and was only getting bulbs. A few other screws I undid were just "holding" pieces of flat metal. I honestly don't know what those pieces of flat metal are. Looks like they go up to the playfield in some way but I didn't want to use my flathead and "pry" them up as I wasn't sure in the slightest that was it and didn't want to mess anything up. I did look at the wires that were going into the boards and pushed on them to make sure they were seated correctly but they all looked to be seated pretty well. I tried looking at the diagrams on the instructions but from what i could make of it it was pretty barebones on the underside view. I'm not sure if anyone has or knows of a reference picture somewhere to where these optos are at on the underside that but it would be a huge help if so!
On the flipside, I did get to the optos from the top. However I'm not sure they were the "right" optos. I removed the purple plastic behind the van and removed it, then unscrewed the 4 screws that hold the metal bracket with the switch that actuates when balls get loaded into the turtle van (premium). There are 2 small circuit boards on either side of this bracket that have little bulbs in them facing each other which I'm 95% sure are the optos. I pulled them from the unit (but left them plugged in) and inspected. From what I could tell the wires were all attached. I took a que tip with some windex and cleaned them up just in case. Reseated them and reinstalled.
However, I'm not sure those were the correct ones. Those optos seem to sense when the ball is coming from behind and into the loading door of the van. Unless I'm mistaken those aren't the same sensors that would sense a ball coming into the pizza parlor from the bottom of the playfield (they seem too high)? I tried getting my head down and looking under there but for the life of me can't see anything. I've already wasted 2 hours and I reallllly don't want to spend 4+ hours taking the ramps and van completely apart just to get to whats down there if it's possible to access them from the bottom. Or maybe the optos I was looking at are indeed the right ones and then I'm just fresh out of ideas.
I put it back together and played again and thought maybe I had moved something and magically fixed the problem as it read about the first 10 balls I fired at it. And then a speedy ball off the right flipper that went fast and straight into the parlor that SHOULD have activated my mode just clinked right through without any mode activation and I knew I was still out of luck.
Any insight that can be given here would be super appreciated. So frustrating.