@INTP I have a feeling that you don't understand anything I post, or you are just not reading carefully. Didn't read any tutorial, and if you look/read closely, you can see the other side of "Ax" jumpers is GND. I think I made one thing clear - i triple check everything I do... So I soldered my cable to GND side of the jumpers. No electrical connection between track from PCF address selection and GND / my mod wire...
@bperrybap Since I started troubleshooting this, everything stayed in one position and I do not move with it - so I do not fear about mechanical stress - yet. I would essentially make it more stable when/if I would solve the problem. That also applies on the electrical shorting prevention - maybe it is hard to see it on the 2D photo, and I moved the cables a bit to get a good shot, but there was no way of short circuit. For the soldering directly on SMD pins - yeah, my first time bodging on SMDs, i could've soldered the other mod wire to the corresponding pull-up.. But I tested it carefully with the continuity tester as I said. About glue - it is classic "hot snot" silicon from glue gun. I could've used less, but the display is little bit far from the actual place where I glued it. That being said, I was relying on the fact I never had a problem with an LCD and glued it before testing... My bad. But this type of glue is easy to remove in the case of change etc. Yes, PCB mounting sounds good, but unfortunately I was not able to do it this time. Time is one of the factors. Thanks for taking your time to improve my thinking, you have made some very good points to consider in the future.
@cattledog sorry I didn't see your answer, my bad. You have a good point and I will probably do that, as it is the most possible thing right now...
That said guys, thank you a lot for your time and insight, you have made some very good points... Will have to wait for the new display... Agrhh