The hall sensor errors are normal if the motor was not turned over or running during the read process. You can ignore them. That does however not mean that they are not faulty. Is the hall sensor you installed a new unit? Or is it 2
nd hand?
These units often work fine while cold but fail as they warm up.
You need to determine if it is a spark issue or a fueling issue. One of them is missing. Could very well be a fuel pump if the bike has been standing for a while. Can you hear the pump prime when you turn the ignition on? Fuel pump is the same as the BMW 318i.
Check for corrosion on the mini relays. Relays 7 & 8 are critical. 7 is the fuel pump relay, 8 is Motronic relay. You can exchange the mini relays with one another in the same row, provided they are all the same colour. Incidentally, there are black and yellow relays (and some blue) on the later bikes. The functions are exactly the same, but I think the yellow ones have a higher current rating than the black ones. If you need to replace them, replace with the yellow ones (Part number: 61 36 6 902 041)
Check fuses 5 & 6. 5 is Motronic/Diag connector, 6 is fuel pump.
WRT the sidestand. My recommendation would be to unplug it and bridge it out. As you have discovered, it cannot just be unplugged. Here's a pic of how to bridge it out. Just use a crocodile clip test lead the short out these 2 pins. Or (if you feel like cutting into the harness, which I wouldn't recommend) splice the wiring behind the connector. Yes, Wayne, it is exactly the same as the 650.
Hope this all helps!