So, I took a quick look at a mostly working Fish Tales and here are my findings and thoughts. I say mostly because it has been sitting kindof apart for a couple of years. I put a ball in the shooter lane but would not launch. Other coils were firing but after all drain it did not put another in the lane so it might have blown a fuse. And a bunch of lamps are out. Thanks, now I have work to do.
Anyway, when you start a game the inlanes on both sides are lit. So the left lane lit and flashing might be working but maybe the LED you put in is a flasher or causing and issue. I'm not a big LED guy and I have seen way too many issues caused depending on the LED and system. I would take out the LEDs and put incandescent bulbs in all 4 sockets until you are sure the game is functioning right. Why introduce extra variables.
Looking under I think the boards are wired the same. The fact that the left in-lane, right in-lane and 2 specials in the outlanes are 48, 58, 68 means to me the issues is right here. Same row, two are wired together, you just did diode work...
Don't do anything until you put in 4 lamps ant run through the test for single lamps.
Here are my boards -
FTLeft (resized).jpg
FTRight (resized).jpg